Now, I wouldn't have raised the rents for the first year for the current tenants, as a gesture of good faith, regardless.

Allowing them the non-refundable fee would be a nice gesture since they will deal with the short-term issues, but ultimately you deal with long-term issues of having a pet in your property and should receive the majority of the monthly fees.

A small gesture goes a long way.

You can continue accepting late payment, but the nice gesture from you to discuss late payment WILL NOT CHANGE WHAT THEY ARE. 

@Frank PatalanoThat's a very nice gesture to pay for someone's admission price for meetup.My heater furnace went out last week and it was the original from 1987.

Your tenants will appreciate the kind gesture and will hopefully not lose their keys again :)

He realized 5 days before lease expiry and as good gesture he brought this point to landlord's attention while giving the keys.

It's sad, because the parents mean it as a grand and generous gesture, but it can cost the recipient tens of thousands in taxes that could have easily been avoided.I hope you have spoken to a tax professional about the specifics of your situation to make sure you know the tax consequences of this action.

@Wayne BrooksOh and @wayne brooks thanks for your feedback greatly appreciated you kind gesture!

There's furthermore a magnificent chance that any gesture you make with a book about home maintenance will be interpreted as an undercover effort to tell your tenant that they're on their own if something goes wrong and not to call you.