If you don't use immune foes when you were planning on doing so then you are invalidating this players choice, and taking away the agency they showed during character creation.
You will also impact other players who might wonder why you aren't skirting around their weaknesses - or worse, why they bothered to create rounded characters instead of ...
Not all scrolls are Spell Scrolls. There is a Scroll of Protection. Granted the list of scrolls that NOT spell scrolls is limited to that one scroll. The section on page 200 is specific to Spell Scrolls.
The effect of the two rules is that anybody that can read a written language can use a Scroll of Protection while you need the spell to be in your class' ...
Remember in D&D RAW, specific overrides general.
The general rule for scrolls "any creature that can understand a written language can read the arcane script on a scroll and attempt to activate it" is overridden by the specific rule for Spell Scrolls: "if the spell is on your class's list you can use an action to read it...otherwise the scroll is ...
You indicated that the player has an interest in picking utility spells when a suitable lightning based spell is not available. I recommend steering the players towards spells whose utility can make a big difference in a fight - there are many useful spells in this category. Also, steer them towards metamagics that can increase their ...
That would be very powerful.
Let's compare the effect with the other things Wish can do:
You grant up to ten creatures you can see immunity to a single spell or other magical effect for 8 hours
You undo a single recent event by forcing a reroll of any roll made within the last round
You grant up to ten creatures that you can see resistance to a damage type ...
About the Rules
You are correct that even if you can do something as much as you want, it still takes time to do. Something that takes your action in combat should not be do-able more frequently than once per 6 seconds outside of combat most of the time (there can be some exceptions, but spellcasting would not usually be considered a candidate for that). So ...
A long rest is interrupted by giving up on it
The text is ambiguous, but 1 hour is meant to apply to the whole period of strenuous activity, while the list is there to define what types of activities could make up that strenuous activity period. The intention is that the rest has to be started over not just for any interruption, but for those unusual times ...
Yes, you can do this
That's how it goes. Spell slots are regained at the end of a long rest, and there's no rule forbidding spellcasting during a long rest.
It's effective and somewhat cheesy, but not as broken as it might sound at first. To cast that spell before ending the rest, you need to save up a slot for it. If you intend to do this constantly, you ...
The caster continues casting the spell.
Taking the same quotes from @Xirema's answer, we have the following for casting spells with a long casting time:
Certain spells (including spells cast as rituals) require more time to
cast: minutes or even hours. When you cast a spell with a casting time
longer than a single action or reaction, you must spend ...
Only if the spell says so
There are spells that can direct multiple attacks against the same target, but they use different language. Instead of saying to choose a number of targets, such a spell says that it creates a number of attacks (or strikes, or missiles, etc.) and then requires you to choose a target for each attack. Some spells that use this ...
You can end concentration at any time (no action required).
As it says above, you can end it at any time, no action required. It means you don't need to use a reaction, so you can elect to just end it.
Which means yes, you can end your concentration as an enemy approaches so that you drop out of their reach.
The Spellcaster would lose the spell
This is relatively straightforward. The rules for spellcasting state unambiguously that a caster casting a spell with a long casting time must use their action each turn to cast it:
Certain spells (including spells cast as rituals) require more time to cast: minutes or even hours. When you cast a spell with a casting ...
"1/X Caster" is shorthand for how quickly a character gains "spellcaster levels" (and with them, more spell slots)
The progression for each of these spellcaster types looks like this, with the first column representing Character Level as a Single-classed X and the other columns representing the "Spellcaster Level" they have as that Single-classed X at a ...
Player's Handbook p.203
Once a spell is cast, its effects aren’t limited by its range, unless the spell’s description says otherwise.
From your example, Heat Metal says:
Until the spell ends, you can use a bonus action on each of your
subsequent turns to cause this damage again.
There is no range or LoS limit on this - they can run but they ...
Yes, player characters can cast their spells at any time unless something explicitly prevents them from doing so.
Players can cast spells any time they want as long as it's their turn, they have a spell slot available (if the spell needs one; most non-cantrip spells do), and they can provide the verbal, somatic, and/or material requirements.
This does, in ...
Up to you
Quoting from the rules of the Wish spell:
You might be able to achieve something beyond the scope of the above examples. State your wish to the DM as precisely as possible. The DM has great latitude in ruling what occurs in such an instance, the greater the wish, the greater the likelihood that something goes wrong.
However, "casting all my ...
RAW this should be fine
Given that, as you say, the illusion of armour, then the armour being made real, do not 'harm' the enemy, then there's no reason why this would contradict the emboldened part of your quote: "The object can't deal damage or otherwise directly harm anyone".
The fact that the enemy wizard is now unable to cast spells is simply a side ...
The components are only consumed when specified.
Player's Handbook p. 203 (or here in the basic rules):
Casting some spells requires particular objects, specified in
parentheses in the component entry. A character can use a component
pouch or a spellcasting focus in place of the components specified for
a spell. But if a cost is indicated for a ...
Interesting choice of multiclass, but the answer is still no.
Raging barbarians are subject to the following requirement as you know:
If you are able to cast spells, you can't cast them or concentrate on them while raging.
Note that it does not make exception for how you are able to cast a spell. Off the cuff spellcasting ability could stem from ...
Elementals are immune to exhaustion.
Circle of the Moon druids can turn into elementals at level 10. Elementals have immunity to the effects of exhaustion.
The Beast Spells feature of Druids at level 18 allows casters to cast spells while in wild shape.
Druid turns into a fire elemental. Being immune to the effects of exhaustion, the druid could ...
Yes, it does
There are no caveats in the rules for casting a spell that ends up not affecting a creature. The rules on spell slots just state that when a character casts a spell, he or she expends a slot of that spell's level or higher...
After all, you simply don't know whether a spell will affect a creature or not until you try (like trying to fireball a ...
No. You get to wait to see if the attack would hit you.
It's specifically a reaction to when you were hit and it allows you to rewind and replay the attack as if you'd cast shield before it (using the original attack roll). See the text:
Casting Time: 1 reaction, which you take when you are hit by an attack or targeted by the magic missile spell
This is not how the rule is intended
Instead of adding a proficiency bonus to an ability check, an attack
roll, or saving throw, the character's player rolls a die.
Going by the text in the DMG, quoted above, proficiency dice are used only when making a roll. It does not completely replace a character's proficiency bonus. Using dice to replace ...
The maximum number of spells a character can cast in a round is 3. You can only take 1 reaction per round, although some monsters have an ability that allows them to ignore this restriction.
You can't cast another spell during the same turn, except for a cantrip with a casting time of 1 action.
This means that you can cast a bonus action spell and a ...
In general, the spell attack bonus and save DCs of a Thief with Use Magic Device is given by the following rule (DMG, page 141):
If you don't have a spellcasting ability - perhaps you're a rogue with the Use Magic Device feature - your spellcasting ability modifier is +0 for the item, and your proficiency bonus does apply.
However, in the specific case ...
It refers to the speed at which classes gain spell slots and new levels of spells during their progression. Full casters (like a Wizard) gain spell slots fastest, while 1/3rd casters only gain slots and new spell levels at about a third that rate.
The name "1/2 caster" and "1/3 caster" comes from the Multiclassing rules, which state that if you have levels ...
Since you used the action, you still make the attack
The ability specifically says that when you use your action to cast the spell, you get to use the BA attack. Counter spell is cast in reaction to a spell being cast and causes it to have no effect. Since counterspell doesn't cause the casting to fail, simply the spell being cast, you still used your ...
Exhaustion for your General Problem
If you're concerned about a character exerting themselves for extended periods of time, you may consider requiring Constitution saving throws to prevent exhaustion. For your specific scenario, I could not locate any specific rules associated with extended combat situations, however, swimming for more than 1 hour requires ...
It’s not just cheap components that are reusable. For example, the identify spell does not state that the 100 gp pearl is consumed:
Components: V, S, M (a pearl worth at least 100 gp and an owl feather)
Based on that spell, along with Colin D’s answer, components are only consumed if it’s explicitly stated.