I got one in the depths of last winter and had previously taken stuff to the laundrette (can't stand washing hanging around) but now the weather's better I'm being a bit more judicious.
Here are my thoughts:
Spin out as much water as possible beforehand (cheaper than cooking it out with heat).
Fold sheets etc into four and flatten before tumbling, otherwise they get twisted into ropes.
Put a small dry towel in with the load, to reduce drying time.
Air dry jeans before finishing them off in the tumbler. They take longer/more power than everything else.
The amount of lint I pick out of the filter tells me my clothes are getting successively more threadbare, which I DON'T like but with kids I know their clothes aren't going to be worn more than a couple of years anyway. Important stuff gets better treatment.
Things are softer without needing liquid or those dryer balls. I miss "crunchy" towels actually.
Faster turnaround means we don't need so many changes of clothes. For example DD only has 1 set of judo kit now, not 2.
Stuff that doesn't go in the dryer: good shirts, bras, stuff with "plastic" letters which peel off, thin polyester sports shirts.
I bought a condenser dryer (at a good price) because they let off less condensation into the room. It also has a moisture sensor and stops at my preferred level of dryness.
I should make my money back compared to the laundrette in about 5 years
but It's much more convenient to have my own.