This machine can and should last you the rest of your life. I bought our Rocky in 1991. Twenty years later, in daily use, it still functions perfectly. My only regret is that I bought the doser model. Since coffee is at its peak when ground just before brewing, you want to grind only the amount you are ready to use. Thus, grinding more into the doser and dispensing from it guarantees that subsequent doses will have lost aromatics and flavor.
The other problem with the doser is that the vanes leave a layer of grinds on the doser's floor. On coffee web sites you can find relatively complicated ways to correct this problem, but I found a simple solution: flip up the doser cover, and spin the vanes while pressing the outer top edge of a vane with your finger. The vanes have enough play that your slight downward pressure tilts that vane into contact with the floor of the doser, and sweeps 99% of the grinds down the hatch and into your waiting portafilter.
Last year, as grind times got longer, I replaced the burrs. I'm not mechanically highly skilled, but was able to do the job myself-- a very satisfying experience.
Setting the right grind is tricky. The numbers on the outside of the hopper are meaningless. (My old setting used to be 13. After the rebuild, it's 5.) For setup, with no coffee in the hopper and the chute swept clean, start at a high enough grind number that you are certain the burrs are not touching. Power on, you'll just hear the motor whirr. Depress the lock tab for the grind setting, and rotate the hopper one notch down the scale. Repeat, one number at a time, until you hear a slight metallic sound. Power down immediately! The sound you heard is the burrs just touching. Note that number on a Post-it and stick it somewhere safe, like on the bottom of the Rocky (but away from the air holes). Make sure you never set the grind to that number, or lower, as the burrs will grind their cutting edges off. Now, set the grind to one number higher, add coffee to the hopper, and begin grinding. Test the grind fineness with your fingers. Use a small stiff brush to sweep as much of that grind from the chute as possible, so the residue doesn't affect the next grind. Pick another number, approximating your goal: espresso, drip, French Press or other. Keep adjusting grind numbers and checking the fineness, being certain never to reach that "burr touch" number.
One other trick is to learn how much coffee to grind to exactly fill the portafilter. I turn on the grinder and tap my foot rhythmically, counting the taps to myself. You'll quickly find the number of taps that give you exactly the amount you need.
A final modification, if you don't have children or idiots in the household, is to remove the finger guard inside the hopper. This makes it easier to periodically clean the hopper of residual oils and grinds.