"Fork manufacturers advise absurdly short maintenance intervals. Some manufacturers even after 200 working hours. That is exaggerated. But beware: some manufacturers void the warranty if you ignore this advice. I generally advise hobby bikers to have their forks and shocks serviced once a year. If you rarely bike, you can wait a year and a half."
"Many people claim that oil spray is too aggressive and damages the seals. I have not found this to be the case in practice. My recommendation is therefore to wash the bike, wipe the stanchions and fork seals with a cloth and then spray oil spray on them. That's how I do it."
"If you don't maintain your fork or shock for more than two years, you are accepting irreparable damage. When the oil is used up, the bushings and seals suffer - and there are grooves in the dip tubes. Naturally, performance decreases. Many people only realise how smoothly their fork actually works after the service. So don't wait too long."
"New forks should be sent for servicing after just one year. Why? The manufacturers are stingy when it comes to oil - Rockshox even more so than Fox. More and often higher quality oil is used for servicing. My tip: send the fork and shock in before March - then the waiting times are shorter. With me, the customer usually has the fork and shock back within a week."
You can find this article in BIKE 2/2019. You can read the entire digital edition in the BIKE app (iTunes and Google Play) or the print edition in the DK shop reorder - while stocks last:

Editor