The weather really doesn’t want to be photographed outside for a few weeks in a row. Therefore, it is not harmful to carry out preventive maintenance of cameras, lenses and flashes from time to time. Especially older devices like to stop working properly in the winter. And because I really like to take photos of old devices, there is enough work.
If you are a skilled individual, doing deeper maintenance on a manual lens is not a problem.If you do not have a technical lens drawing, take a picture of each step. For new lenses, do not perform such maintenance without experience.
Do the same when disassembling and assembling the cameras. The photos from the mobile phone will then tell you where the part belongs.