What bending is safe??

What sort of bending would people say is safe? I've heard to try and avoid it at all costs but it's so hard!! I've seen people who are pregnant picking up toddlers before so didn't see it being an issue. And seeing as my normal every day tasks include bending down at some stage I didn't see any harm at all as sometimes there's no avoiding it. Even down to just changing my dogs water and putting her food bowl down. What's everyone else's views on this?? TIA