Maskol instructions say:
Do not allow dried film to remain on the surface for more than 3 days.
I confess I have left it on a model for several weeks but never had any issues with it, a couple of years might be pushing your luck :-).
I don't think any liquid mask could replace a pre made mask or tape for a lot of jobs and visa versa for others.
Would that be a Scotty Star Trek quote Cadet Chuck?? How quaint.