D&D 5E About to run Lost Mine of Phandelver & I have some questions. May contain spoilers.

[Nebulous]

As an estimate on time, my players just finished the 4th session (4 hours a piece), and they just arrived at cragmaw castle. It depends on how long your sessions last, but I'd suggest you put a time constraint on them (which will inevitably be ignored) and start to look for a wrap up point (long rest, back to town, etc.) that will help end the day. Sometimes its unavoidable, but it helps us to have the timeline laid out. "Thursday from 5:30 - 8:30" (Note, that we've never actually wrapped up prior to 9).

Unfortunately we have a hard 2 hour cap on our sessions, usually 6-8pm. Sometimes there's some wiggle room. We used to play 4 hours a long time ago, but current demands on people's time now, well, it is what it is. On the plus side I can add in little interesting tidbits that might not happen if we gunned through a longer session.

We had our 11th game tonight, and it was the third session in the final level, so that's 6 hours they've spent now in the Mine of Phandelver and we're still not done.