i rode for 10 years, then had a 9/10 year break and am coming back upto my second year of being in the saddle again, complete with my own horse (hopefully another next year!) , own horsebox, compete regulary and am having great fun! it's definitely like riding a bike, once you've done it once you'll never forget how to ride.... the difference i found is feeding of horses, and general routines.... nothing like what they used to be!
Oh and also the standard at competitions is incredibly high and good nowadays, i can remember competing on my ex riding school scruffy mare when i was younger and regulary being in the ribbons... nowadays i don't think i could get away with it!
Have fun and enjoy.