What do i owe my tenant?

[Steven Horvath]

Being a first time landlord i was curious as to what more experienced landlords would do in this case.
i have a tenant who has been in for last 6 months and atleast always gets rent to me before the late day.
the first problem i have had was 2 weeks ago the dishwasher wasnt working and i had my friend down the street go over there to fix it- it just needed a reset. i did not charge anything. however my tenant just called me saying the faucet on the tub is leaking, i know i can go over there and fix it in 30 minutes but is this something i can charge him for, my time basically, or is this something that just falls under my responsibility. I had a realtor rent my house being it was my first time and i had no clue what i was doing, but i am lucky in that i have the texas realtors association lease agreement which states they are to pay the first 65 for visits/problems. everything is new in the house. so do i charge them or just fix it? if i can tell it was damaged becuase of neglagence i am assuming i would def. charge them.
Also this is the first time i will step foot in the house since i rented it to them, is it ok if i check the A/C filter to see if they are changing it? if there is anything else i should check out the first time i go in i would love to know, i am reading/doing everything i can to get my knowledge base up just a lot of stuff to learn.
Thanks!
steven