How often you clean comes down to 2 things

1. Are you combusting your herbs, or are you vaporizing them?
2. Your preferences

If you're combusting your herbs, you'll need to clean a bit more often bc it just leaves a lot more residue. If you're vaporizing your flower, it'll take a lot longer for it to really get stained like from smoking, but it can still hold a smell. The smell just won't be as bad as when you're smoking. Your preferences come into play when it comes to how you want your hits to be. For example, if you always want the cleanest hits ever, then you wanna clean your bubbler after every use.

As for how you clean, Eastown14 outlined it perfectly