Maintenance and restoration of decks is a time consuming and hard task. If you go for the annual maintenance there will be a lot of tasks to be accomplished and taken care of.  This might turn out to be a major overhaul. 

On the other hand if you take care of small things as and when they make their appearances, at the end of it you will be the gainer. You will find during the annual maintenance that your tasks have been substantially reduced thanks to your interest in meeting small contingencies on the spot.

For example you may take up cleaning of your deck using deck cleaners on a periodical and regular basis instead of going for the annual cleaning. This will not only keep your deck looking neat and clean and good but will also enhance the longevity.

Removal of unwanted wood stains would be an added bonus. The best part of it is that when you really go for the annual cleaning, you will have very little to accomplish since most of the tasks have already been taken care of. 

Quality sealers or stains will remain on for 18 to 36 months. The life span will be more on the vertical decks. One of the major utility of the sealers or stains is that it protects the deck from harmful ultra violet rays just as your sunglass protects your eyes from sunshine. Therefore, if you wish to use deck stains or sealers to maintain the glossy appearance and to protect it from harmful environmental influences, you may go for the same periodically.