My first vacancy was the longest … took about 5 weeks to fill (that was in the early 2000’s).
After that we’ve always priced on the low side, advertised before it was vacant, usually 3 or 4 weeks ahead and have always had a rental agreement before it was empty. Of course in most of those cases the place was vacant for 1-3 weeks due to post-move-out/pre-move-in painting, etc and/or timing of the desired move-in.
Again, it will depend on many things you cannot really control and some things you can.
You can’t control the size of unit, location, or it’s overall condition (OK, you can control that somewhat, but probably not cost effective to gut-remodel, etc)
Your only real levers are price and terms
Terms might include pets and lease flexibility (e.g. allow 6-12 month).
I’ve found that if I allow pets I often lease it quickly at a good rate. Of course, if my property were pristine I wouldn’t allow pets, but its condition is suitable for pets.