i couldnt agree more with yaakov
alot of times suits will run you around like that to get outta signing a pm contract etc
a big selling point on pms,, in addition to mr yaakovs, i use is having a trained set of eyes on the machine that can spot condotions that will lead to an eventual breakdown then the tech can recomend repairs that will be needed to catch it before it makes the problem worse of potentialy hazardous or fatal

some examples would be worn forks (ive seen people lifting 5000lbs with 30 to 40% of their forks shaved off)
worn hoses loose fittings
worn axles wheel bearings etc
worn mast components
bad brakes
worn contactors and electrical components
bad batteries (that will lead to major damage to the machine)

correct poor charging/ battery habits (i love the guys who tell me, after their industrial battery fries up and i tell em the price for the new one, that "you guys filled the water on the last pm 3 months ago" and no one has checked it since and they use it 8 hours a day lol)

also specific problems that are found often in a certain line of machine
example when mitsu changed the design of their tilt sockets a few years back the thru bolt used wasnt torqued down enough on a lot of machines and wasnt picked up on the delivery inspection. eventually they would pull the hydraulic rod right out of the socket stripping both the socket and the rod. depending on the damage the socket almost always has to be replaced and sometimes u can rethread the rod either way though the customer was down a machine at least a day plus and expensive repair.(some come loose on their own on all makes and models of lifts and is important to check on any pm) we always check those thru bolts and readjust the tilt cylinders when one is loose that takes 5 mins tops durning a standard pm with no extra charge (since its easy to fix when you catch it)

tip the best way to tell the tilt is out of adjustment is when u dead out the tilt and the mast almost looks like it 'twists' alittle

also it always makes a customer happy when you tell him how you just saved him 600 bucks for the cost of a pm

you would be surprised what an operator wont report
i had one guy tell me, when i asked if he checks the oil on his preshift inspection, "i just get on and drive it. if the wheels fall off thats someone elses problem" i told him "until u drop a load on someone elses head and kills em after the wheels fell off"

as a tech in a busy shop in metro new york you do see a differance between the guy who does his regular maintanace and the guy who dosnt. it shows in the frequency, severity. and downtime of breakdowns