Maintenance to prevent clogging?

We live in Western Europe (Germany). I don't know if that is relevant because of the difference in plumbing and the like.

How can I prevent clogging? One plumber said, we should dump a bucket of water once a week in the sink, and use the shower hose (without the head) at full capacity for 1 minute angled at the drain in the bathtub. Is that solid advice, and what about the toilet? I am thankful for any help.