Wheels, brakes etc. must be cleaned and maintained regularly.
For plastic joints we recommend Vaseline for lubricating. Please remove wheels and apply the grease cream thinly. Inaccessible parts can be treated with spray oil (WD40).
A long service life also depends on regular cleaning. The waiting should be repeated every few weeks depending on the strain. This prevents increased wear due to friction and of course annoying squeaking and enables an easy run.