Sharpening them yourself isn't that bad. I have mulching blades on my 60" deck and I've sharpened them once a year for 10 years now. You can find lots of info on sharpening in the archives. Our pocket gophers push up big mounds of the clay, as well as rocks that are down in the clay. Though I try to kick them down before mowing, the blades still hit lots of rocks.
Basically, You need a wooden block to stop the blade and a big wrench, or at least a cheater pipe to extend the length, to get the blades off. You need a bench vice (preferably bolted down) to hold the blades, and an angle grinder. I got my vice and grinder from Harbor Freight for about $20 each. They come in handy for lots of other stuff too. A cutoff disc on an angle grinder cuts through metal much easier than a hacksaw blade on a reciprocating saw.
I won't go into grinding technique very much here. You need not to overheat the metal, though, so you don't distemper it. Wear eye protection. Be aware that grinding perpendicularly to the blade leaves a concave cut (can't remember the big vocab word for that right off); this can be minimized by turning the grinder and somewhat grinding with the planar (flat) side of the grinding disc. the more chamfered/beveled the edge, the thinner and sharper the metal, BUT the shorter the time it will stay sharp. New blades have a crisp edge but are around 80 degrees. You don't want an edge like a knife. I sharpen mine to about 40 degrees.
It's important to insure that the blade is balanced. Unbalanced blades can cause excessive vibration when the MMM runs. There are fancy gadgets for this task, but I just hang the blade on a little finish nail I have sticking out from a wooden storage shelf and make sure the hole is centered on the nail. If one side drops down, I just grind a little more off that side until the blade balances.
Clean the deck while the blades are off. When you put the blades back on, torque appropriately. Make sure to hit all the zerks with a grease gun. Check the belt.
Remember-tons more info in the archives-use the search function. Hope this helps.