There is a tool available, it is a little cyndrical piece that clips over the line, then you slide it into the white piece and it undoes the clip for you. I have always gotten it by hand though,but some guys at the shop prefer the tool set (includes several diferent sizes). They prefer it becouse it pushes the clip evenly and there is less chance of it getting stuck.

As for how long your clutch should last it almost always debends on the driver. Yes there are cheap rebuilds that wear out faster, but you will find that someone who rests there foot on the clutch pedal will wear out the clutch and the bearing faster (and since the bearing is part of the slave you will have to replace it sooner).
And I have found through personal experiance (these are just my personal findings and may not be completely correct) that someone who jumps on the pedal hard and fast, will wear out the hydrolic parts faster, and peaple who have the tendancy to hold the clutch down while sitting for a long length of time (waiting for a slow train for example) will wear out the hydrolics (primarily the master) faster than someone who puts it in nuetral and releases the clutch.

If you are at 73000 and replacing the hydrolics already then the po might have bean someone who "jumped" on the clutch instead of releasing steadly. Again this is just my personal theory and may not be entirly correct.