Once a year is a minimum recommendation--a lot of people do that. There are also a lot of people who prefer every 6 months, just to keep in contact with the vet and keep the vet up to speed about how the hedgie normally acts. Try to go at least once a year.
Hedgies can live a long time. Some have lived to be 10. Cats and dogs can live longer than that, definitely, but I wouldn't consider 4-8 (the average) and possibly 10 to be short. Let's hope to see a lengthening of that time as knowledge for care improves.