do you have sand or gravel ? (I know you said gravel, but just checking)
Planted with gravel, it shouldn't be a problem and you don't have to move things around on a weekly basis.
Once every few months is good to lift up heavy ornaments though and give a good vac underneath wood, slate etc.
Just go very gently around the plants and don't disturb the roots too much (if at all).
With sand you've got to be careful that it doesn't compact under heavy ornaments, logs, slate - and you'll need to check this on a more regular basis - unless ou have malaysian trumpet snails in there, which should help a great deal to churn things over.