Many times add-on become outdated for various reasons, like an add-on which is not maintained anymore. Having many add-ons also affect your system making it run slower, as those add-ons consume more memory, perform more queries in order to stay updated and occupies more storage.
It is a good practice to go over your add-ons, see which ones are not used anymore and if so delete them. This way you free resources from your system, improve its performance and make it run faster.