With all of that being said, I will continue to offer early check in for free when I know it's available as I do think it is a nice gesture and likely leads to a positive first impression.

We got a new tenant,and she asked for a screen door-- when we picked up rent, she was so happy to show it off, and was so incredibly appreciative, she gave me a hug  and thanked me... it was  a small gesture, but man I felt great after that! 

It's a great gesture for sure.

It is a scientific fact that people’s gestures give away their true intentions.

Offer to take them to lunch or something as a gesture of thanks.

They are $1.00 apiece so more of a gesture then a money maker.

They can certainly asked but treat any amount of money as a gift or goodwill gesture and expect a hard no.

I'd pay the overage if they are good tenants, that gesture will probably go a long way.

Rent is ~500 per month/unit.So far I've only received one complaint because the contractor was working late one night, but I would like to offer a gift or rent reduction to the other 3 units this month as a gesture for putting up with the disturbance.Any suggestions or things to consider?

when putting up earnest money to get a property under contract, if is a good faith gesture signifying that you intend to buy or have/find a buyer... understood.