One thing about the typical bike that plagues most are flat tires. Used to be a tube was made for a rim size so if you rode a fat tire bike you had a fat tire sized inner tube. These days it's all about universal fit. So say you ride on 28mm tires the universal will fit fairly well and blowing it up to max pressure does stretch the thin rubber very much.
That same tube all blown up inside a 1.75" or fatter tire stretches the thin tube even thinner. If the tire is not blown up to max pressure pinch flats are a huge problem. Back when tubes were sized per tire size they were thicker also, so pinch flats wasn't a big deal.
I'd invest in a pump with a pressure guage and keep the tires inflated at least the minimum pressure indicated on the sidewall.
Keep the chain lubed and clean it every so often.
Coaster brakes are the most reliable.
A decent lock will help make sure it's still there when you leave the doctor or store. Being a "cheap" bike most won't bother with trying to cut the lock like they would a high end bike, but it will keep the average klepto from peddling your bike instead of you.