Are you serious? I can't imagine anyone doing a good job in 30 minutes. I am assuming that the job involves jacking up the vehicle, removing the axles from the car, removing the old boots, cleaning out the old gease, packing in new grease, installing new boots, reinstalling the axles, lowering the car and cleaning up. If you can do that to both sides in 30 minutes you are awesome. I've never done it in 30 minutes to a side, but I don't claim to be a professional. I think the last time I did it to a Jetta, it took me a couple of hours total (from in the garage, to out of the garage, tools put up, bay cleaned up).
Ed