Hi JDuc, It is a good idea to do the first fork service within the first 6,000 miles as the forks are subject to break-in. Keeping the fork oil clean will help your forks last a long time as well as perform like new (or better if you do a kit). Other than the initial time, changing the oil and cleaning the fork internals should be done every 2 years or 12K miles. The same for the shock. If you ride in dirty conditions like dirty wet roads or you live on a gravel road, shorten the interval.
The forks can be a great DIY project if you enjoy doing that stuff. You should have a couple special tools (I can list if you want). If you have other things to do it is more efficient to have a good shop (like us

) do the work. We charge $100 to do the forks. Any parts are extra but we discount those better than anyone regardless if we install them or sell them directly. Shipping for forks is about $19-20 each way via FedEx ground service. If you do choose to do it yourself, plan on dedicating the weekend to a satisfying project. I am happy to answer questions. I plan to do a DIY page on our site...
The RaceTech Gold Valve kit along with some correct rate springs are a nice mod for the DIY person. The kit comes with a good set of instructions as well as a video. This mod is highly recommended for the Monster, ST and SS bikes!
The Penske kit takes it to a whole new level but must be installed by a Penske Authorized shop. We have the most experience with these kits on Ducatis. That install includes special polishing and preparation of the fork internals.
Having said all that, keep all your suspension parts well maintained and set you sag correctly as the first step. Having the correct spring rates for your size and riding style is the second. The custom damping setups are way worth the time, effort and money. You can go nuts from there... Ohlins Superbike forks, anyone?
