Rebuilding Ohlins steering damper?

Hi there,

Can anybody shed some light on how often and whats involved + costs in rebuilding an Ohlins steering damper.
I read the other day that racers rebuild every 4th or so race. The damper still gets stif on full adjustment and I have had the damper for 2 years now.
Or am I just suposed to service the damper frequently to keep it in tip top condition?

Any advice would be grately appreciated.