Also NEVER mention even in passing something you would like to do to the property like “I really would like to install new windows or repaint the exterior of the house,” etc. because the tenants will pester you about it until you do.  

The tenant’s action is irrelevant to the fact that three years have passed and the landlord has to repaint, crayons or not. 

Even so a couple weeks sounds fair if it is a hefty turnover with a full week of work for full repaint and a trash haul. 

I rehabbed a 1978 home with all original cabinets and I repainted them, added new hardware and I swear you cannot tell the difference between them and new ones.

Repainted the walls etc with 'mold suppressive' paint & again upgraded the old exhaust fan.

It ain't much and it wouldn't pay to repaint the room they stayed in, but the psychological effect is present and that works.

Thats also a BIG house , what do you think it will cost to repaint ? 

Generally easy to fix.If you're thinking about changing to completely different window coverings, you will need to take down the head rail and patch the holes in the wall and perhaps repaint.

Third, when you have tenant turnover, you’ve almost always need to repaint the interior - that’s on you, not the tenant.  

I wouldn't let them repaint or do anything major until your lease is up.