Time between level-ups: always the same or increasing?

[Ahnehnois]

10 sessions is, give or take, about the average length of a single decent-size adventure for us.

My last campaign took 1st level characters trying to make a living in a small village to fated 8th level characters who find an artifact that brings about the setting's armageddon/ragnarok event. It was planned for 20 sessions, but had to be condensed down to 12 because of lost time, and I really had to get it done before two of my players got married and went on honeymoon. Still took almost a year. And despite the fact that it finished over a year ago, I haven't run a campaign's worth of sessions since, due to trying different games, spreading around DMing, and being busy.

That's my reality.