My basic questions are :Siding 30 -40 years old showing some wear and tear - replace just paint or just power wash the siding and roll with it.

I was driving by an apartment complex this afternoon and while waiting for the traffic light to turn green I noticed a guy painting the exterior wall of the apartment with a roller.What really caught my eyes was he outfitted himself with some contraption. 

Get 2 good rollers they wash out really good & when you finish & will be using the roller again the next day instead of washing it out wrap it good with saran wrap.

I'd use Michael's advice -- wash the walls a couple times with TSP + water.

The washing machine didn't work and the hot tub was touchy too.

What's the best way to wash those filters?

We solvent weld all plumbing with a union installed and then put linoleum in the cabinet.

The tenants using it are likely purchasing money orders anyways, so it's a wash.  

But, now they're saying they are ensured a certain amount (extra fee), so many cents on each wash (another fee), things like that which push my part down to 35.43%.

About the only thing I do while the tenant is living there is to pressure wash the exterior once a year.