I'm gonna second the fifth wheel greasing. (That was a bit a pet peeve of mine.)
Check the air in the tires daily. I gauged mine every morning and kicked or thumped every time I got out.
Look the truck over when you stop. It's not going to hurt anything.
DO NOT BE AFRAID TO GET OUT AND LOOK.
If it's not a hard surface get out and walk it if you have to.
If you're not comfortable DON'T DO IT!!!! Don't be afraid to say NO! KMA!
This one I'm not sure to pass on because it might get someone in trouble, but for flatbedders, if you have a tall load and your straps are flapping violently you can put a single twist in the strap on each side of the load and it'll stop that.
Always be on the look out for material that can be used for padding to prevent holes in the tarp.
Carry a tarp repair kit.
If you're a company driver who has an assigned long-term truck, it could be worth buying your own higher quality wiper blades. Many use the cheapest they can get...especially megas. And they don't always clean that well even when new.
Harder to do/afford when you slipseat and might not see the truck again.
Keep a small window squeegee in your truck like you see at most car gas stations.
Couple swipes and you can get that rain buildup off your mirrors to dock easier, and you won't have smearing.
Better still, keep a spray bottle of washer fluid with you so you can properly clean and squeegee anywhere, no need to wait until you fuel.
I carry a spare, coiled, electrical cord. I can unhook both ends of the cord on the truck and trailer, and use it to get me home or at least to a place to park. It being coiled keeps it off the catwalkI like to have several extra bungee cords.If I hook up to a trailer and the electrial cord/lights ain`t working too good,I can hook a bungee cord to the pigtail and to the front of the trailer somewhere and usually all the trailer lights work.