How do raising skills work in The One Ring?

Question

When the adventuring phase ends, PCs can use their advancement points to raise common skills and experience to raise other stats. I hav several doubts about that:

• Is advancement points the only way to raise common skills, or experience can also be used? The advancement points seems to be very few to raise even a single skill, and also there's at least one point where you can use XP to raise common skills: character generation. If XP can be used, how does it combine to AP?
• Must AP be used on the same skill category they were earned or are they just pooled together and used en whatever skill you want?
• How does the system has worked to you?

I know this is explained in the core books, but it seems I fail to understand the rules.

Answer 1

The two are totally separated. You spend your advancement points on common skills. You spend experience on combat skills and Valor/Wisdom levels. And they reinforce thusly what you've been doing with your time.

SPENDING EXPERIENCE POINTS
Heroes may spend their accumulated Experience points to gain a new rank in either Wisdom or Valour, and to enhance their proficiency in their Weapon skills.
(TOR AB p. 170)

Note that it does not list common skills there. Thus it's not allowed.

SPENDING ADVANCEMENT POINTS
Players spend Advancement points to raise their Common skill ranks, using the costs in the table below.Players are not obliged to spend all their Advancement points, but may save them to acquire more expensive upgrades during a later Fellowship phase. Players can also buy multiple ranks into the same Common skill, as long as they pay the cost of every new level individually. Any remaining Advancement points are kept track of using the appropriate space on the back of the character sheet.
(TOR AB p. 171)

AP are pooled - at the fellowship phase, all your marks are tallied, and then you add that total to your available AP. Note that there are only 3 AP per category, and unspent go in the single box on the back of the sheet... and the lowest cost upgrade is 4, so it's impossible to use a single category's AP total to raise a common skill.

Yes, the system worked quite well for me - the separation of AP and EP forced players to use their common skills in order to raise them. Combat is easy - XP are earned pretty steadily. The gaining of abilities and magic item by Virtue and Wisdom ranks worked particularly well.