Septic Tanks

Dear All

We have always been on mains drains.

Considering moving to a property without. Septic tank instead.

Need some advice please.

If you have one, does it make the garden smell periodically (depending on weather/temperature etc), how often should it be emptied? Have been told you cannot clean your toilets using bleach and that you have to use special sort of loo rolls.

Any useful information on septic tanks and related "fors and againsts" would be most gratefully received.

Thanking you all in advance.