I recently started running a game of D&D 5e for 4 brand-new roleplayers. I designed a short adventure to introduce them to RPGs and to the D&D system and they enjoyed it a lot and wanted more. Since then we've had one session where they have begun to play a slightly modified version of the Lost Mine of Phandelver with the same characters.
However, we're all busy people with busy schedules and we've been unable to find a time for a regular game. Our last session was 3 months ago and it's looking like another 2 or 3 months before we will have time for another (one player has said she simply doesn't have time for a regular game).
I'm not sure yet how this sporadic gaming will affect the players, but I know I'm going to find it hard as a DM to keep track of what the characters have accomplished and discovered, who they've spoken to, etc. I'm worried that for the players, they may have trouble remembering what it is they're supposed to be doing and why, as well as the above points.
I would like to hear, from people who have experienced similar situations with groups, how can I make a fun, immersive, coherent game when the sessions are very far apart?