Only time i'd stick into a garage for anything is if it was a two man job or required ramps, don't think I've let a garage do anything other than Mot's and tyres in about 5 Years on all our cars and bike, If I couldn't service a car or bike then I don't think my work would be happy letting me loose on all there machinery! I'm no expert, I'm always learning but there's always plenty of guides or drawing to help as long as you can understand them and understand why you do what you do when your are doing the task not just blindly follow instructions. when buying a car that's been self serviced I'll look for receipts and grill the owner to see if they know their stuff.