Crawling and saying no

My 9 month old has been crawling for almost two weeks and as she started I realized that mobility is really the first time a baby meet limits. We have our house baby proofed but obviously there are things we don’t want her getting into and I want to teach her to respect boundaries. So far I’ve been trying to say “ah ah, that heater is hot and you could get hurt” or “ah ah those are daddy’s boots, we don’t play with daddy’s shoes” because I really don’t want her to hear “no” all the time... I’d rather reserve that for very dangerous things like crawling off a bed or running near traffic. Anyway, I’m just curious how everyone else is setting limits early on? Sometimes I catch myself thinking “no, don’t chew on that book. You’ll ruin it!” which is how I was raised so I’m trying to be very conscious since this kind of approach doesn’t come naturally.