I said that we bought the place over a month ago, we served a termination notice, which the tenant signed, then the tenant sent us a text message stating "He is done, he is out of the place" and that we changed locks yesterday, nothing was left in the house and only the garbage was left outside around the dumpster.

For example, we've provided packing boxes and 3 mil garbage bags to tenants whom we have asked to move.

You feel like you never have time off, and it can get so you don't want to take your garbage out because some tenant might see you and start yakking at you.  

So far I’ve filled about 15 garbage bags with food, clothes, and toiletries.

If they are power hogs or water wasters let them deal with the bills themselves.Trash should be the only thing covered by rent to insure service every week and doesn't get stopped by non payment.Don't give them an excuse to let garbage pile up and attract insects and government fines.

One of my tenants left without paying rent. and left lots of garbage in the house.

Bring lots of garbage bags (preferably contractor grade) as most loose stuff / junk probably hasn't been packed and can be "gently" placed in garbage bags and hauled outside.

They didn't leave the place really clean normally, but at least they removed all their junk, even if a lot of it ended up piled around the garbage bins LOL.  

In my contracts I so spell out pest management techniques that must be adhered to regarding sanitation and etc. and if they do not I can actually charge them if there is say a rodent problem and it is because they leave garbage outside a garbage can blah blah blah. 

It is really up to you as a landlord to decide whether the calculated utility rates for your area are advantageous to you to include in your rent (water, sewer and sometimes garbage often are) or aren't (power and gas usually are not).