I would also add that if filters need cleaning at shorter intervals, like weekly or even bi-weekly, then perhaps some mechanical assistance is needed. Bio filtering may be adequate, mechanical may be lacking. Not really harm to fish, just more work for the fishkeeper.
It is pretty easy to have Ammonia and Nitrite always zero once a tank is cycled. The challenge becomes keeping the nitrates, say at 20 or lower. That is helped with frequent water changes and lots of filtering will catch debris and uneaten food and fish waste that can be removed with adequate filter maintenance.