In EE WW (my Xmas game) the first level has almost 10 000 and in my larger project on one layer it's about 35 000. I need to split frames sooner...
I don't like using quick backdrops because then I have to go through and change them all if I update some graphics, it's not fun for tile based games. If your game runs on a level editor you're very likely going to get close to that limit at some point too.