Hi folks,
First, thanks everyone sharing your experience 
Answering the initial question - I use several dozen of lists, but not many active at the same time. Using ‘ll’ popup to quickly switch between them (basically, ll, then type the part of list name with is interesting to me). I don’t use lists which are large (i.e. > 3000 items)
For time-bounded tasks, Due page and repeating tasks with e-mail notifications work fine for me.
Oh, and lists are tagged as well, for extra organization. Checkvist related lists are tagged #checkvist, too.
Just wanted to let you know that in this year, we hope to
- bring a better bookmark feature
- improve global cross-list search
- improve performance for large lists (not a trivial issue, but let’s see)
But first, we’d like to enhance working with links even further.
All the best,