Depends when it was last serviced and which service it was as VW specify various intervals:
Every 10k: oil change
Every 12 months (check hoses for leaks, brake pad thickness, etc and oil if covering less than 10k a year). Basically this is just a check of components.
Every 20k: all above and spark plugs, air filter, etc.
If you want a full breakdown let me know as long list in Haynes manual and this is only a summary. The crucial thing to check is when and if the cambelt and tensioner have been replaced. if never it is worth doing asap, just to be on the safe side.
