What I learned as a renter is ... if you get a good landlord, who doesn't raise the rent to market rates every year, be very nice. Fix stuff around the apartment. Don't call them for every little thing. Those landlords are hard to find.
There's a flip side to that, though. If you get a good tenant, try to keep that person.
Everyone wants a tenant who pays the rent on time, doesn't trash the place, and who doesn't bug you about every trivial problem such as a light bulb that needs changing or the fact they're out of toilet paper, cherish this good customer. Make repairs promptly and stay accessible, but don't hover.
My best tenant demographic, bar none, has been people with disabilities. I'm not suggesting that people reverse stereotype, because bad tenants exist in all demographics and you do have to screen for them. But in terms of bang for the buck, I get a bigger bang when I go after this customer group, possibly because the community is under-served.
In the lease for the property I rent out, I have a clause that the first $100 of every repair is on the tenant. This does 2 things, 1) encourages the tenant to care for the place and not screw it up, and 2) discourages the tenant from calling me for every little thing ("Sure I'll come change your lightbulb, it will be $99 please").
Now, the flip side is, the last tenant I had, I had 2 things break and neither was the fault of the tenant (ejector pump and dishwasher circuit fried). I waived the $100 fee because they were very good tenants. And I told my latest tenants the same thing, the clause is there if I need it, but I don't intend to enforce it because once every 6 months something legitimately breaks.
Is that legal? If stuff breaks (garbage disposal, toilet, fridge, etc) a renter shouldn't have to pay a cent and it shouldn't depend on the landlord deciding to make an exception to the lease.
Also, I would never sign a lease with that clause, mostly because one of the advantages of renting is that someone else is responsible for the repairs. As in, if the drain clogs, it is actually not my responsibility to fix it, it's the landlord's. Damned if I'm paying for something that's someone else's responsibility.
Much depends on the kind of property you're renting. A single room in my home where two tenants share a bathroom works differently from a single family dwelling with separate metering.
A single family dwelling can come with a duty-to-maintain clause since the occupant controls the building. Not so with shared space, and if you've got a 4-plex some of the sewer pipes may be shared so it could be hard to determine whose "fault" something is. With a condo you only own things from the sheetrock in, so if you rent one out there's an entire new layer of responsibility when it comes to clogged pipes: you (or your tenant) may have to call the building manager.
Generally you can tell by looking at an appliance or window whether or not it wore out. I have yet to run across a set of state laws that allow you to bill the tenant for wear and tear related expenses since all US states have laws that derive from the UORRA. Wear and tear is a cost of doing business and should built into the rent.
When deciding whether to pay for a fix myself, I ask myself a few questions.
(1) If I were living here myself, could I have predicted or prevented this damage?
(2) If this tenant moved out today, would this repair be a legitimate deduction from the damage deposit?
(3) Is the damage the result of behavior that would be unacceptable at the workplace?
(4) Is the work just standard maintenance related replacement of some consumable item like a light bulb or a smoke alarm battery, that any able-bodied adult is capable of doing?
If the answer to all these questions is "no", then fixing the damage isn't my tenant's fault and I make the repair. If the answer is "yes", then the tenant should do the work or pay to have it done.
For example, a door lock that stops working due to age or rust is my responsibility to fix, but a lock that has chewing gum jammed into it is not. I'll gladly show up and unclog a drain once in a blue moon, but when the same toilet clogs every 28 days and my drain snake brings up chunks of used maxi pads and plastic, I have a conversation with the tenant about what should or shouldn't be flushed. I remind my tenants to change the batteries in their smoke detectors twice a year, but unless that tenant is physically incapable of getting up on a ladder and making the fix I rely on them to do it and don't perform that maintenance myself.