First of all, it is important that you charge the battery in question correctly. For this you often find instructions in the supplied information booklet or on the packaging. For example, many of the smaller devices need to be charged with a separate wall plug.
If you do not charge the devices according to the instructions, the battery may become overloaded consistently. Reduce the battery in a much shorter period than usual in capacity. Now it is common with all batteries that they degrade over a certain period of time. We therefore recommend to have a battery replaced after two years at least.