Housewarming gifts are for home buyers, not tenants.
Remember in the Bugs Bunny cartoons when a character realized Bugs was
playing him as a sucker? The character's face would turn into a
lollipop with the word "SUCKER" written on it. That's how 99.9% of
renters see you when you give them a housewarming gift.
About 5 years ago when I got out of the god-forsaken business of being a landlord, I bent over backwards for a tenant I had (which was my last tenant ever). Her rent was WAY below market and I only increased her rent once in that decade because she paid on time, was mostly a good tenant and the apartment was hard to rent (another story). She was one of the few "good tenants" I and my family had in our decades of being landlords.
But when she left, she gave me less than 15 days notice and was moving out a few days after the first of the following month. Yet she had the audacity to get bent out of shape when I told her I would expect her to pay daily rent for the few days of the next month that she would be living there. After all, she was the one who was stiffing me. She could at least pay me the daily rent she rightfully owed me for the following month. But I backed down and did not pursue it as I knew I was out of the business once she left anyhow and it would not be cost effective to pursue the whole thing legally. I only tried demanding the daily rent out of spite for giving so little notice more than anything else. lol
I learned (but apparently not well enough lol) as a little boy from my father when he was a landlord. I noticed every time he stepped out of his role as a landlord and into a "friend" role, the tenant would usually try to shaft him.
Moral of the story? Being a landlord is a business and 99.9% of your
customers (the renters) will always treat their
end as a business transaction. Therefore, you should do the same.
Always
remember what business you're in and act accordingly.
It's not a friendship, it's a friendly (hopefully) business transaction. Housewarming gifts will almost never provide any benefit to you as a landlord. Since tenants usually never expect gifts anyway so not giving them gifts will never hurt you, but giving them usually will.
Friendly but firm is the only way to fly in this business.