which sort of winds me up because if a machine is 20 plus years old its very unlikely that the hour clock is going to even work - and if it is its even more unlikely to show a true reading. 
A brand new machine costing say £50k plus has to earn its keep so if its doing 8 hours a day or 12 hours a day you can expect any machine to read between 44 - 66 hours a week if worked a Saturday this works out to be around 176 - 264 hours a month. Now as we know the construction industry is not constant, machines are switched off for lunches, breakdowns, servicing, waiting between loads, holidays transportation, wet weather sometimes etc etc etc - so the hours on a machine cannot be calculated like a constant running generator or something.
So lets take a healthy average of 200 hours a month and do a 10 month year - that equates to an average yearly hour clock showing 2000 hours.On average a brand new machine is worked for 3 good years before a possible replacement so in the first 3 years an average worked machine should have clocked around 6000 hours on the clock if the operator has got his value out of it.
The same machine after its 3 year work out then usually stands in a dealers yard or auction untill purchased for a second time - This standing time (could even be as much a 3 months) reduces the build up of hours further. The new customer of the 3 year old machine is probably a builder looking for a machine to help build only a handful of houses or even a contractor looking for a backup machine to support his brand new machines and isn't going to put the same type of hours on the machine previously experienced in the last 3 years of service. He has got a great machine tho as usually the first customer will have maintained his machine very well as part of a warrenty or service contract.
The 2nd customer of this machine is probably only going to put just less than half as many hours in this machine in it's next 3 years. So lets say after 6 years from new the machine has accumulated 8500 hours.
Now time for the 3rd customer - this is probably the unluckiest customer
becuause This customer is buying a machine that looks to be quite good value on paper but some of the major mechanicals could be doing with an overhaul - things like chains, sprockets, rollers, slew ring, even aspects of the engine and hydraulic pump may need attention. Saying this potential maintenance work gets done the 3rd customer may only hang on to this machine for a short time - a year or two - this short stay usually is a result of the owner getting fed up having to spend money on the digger
- causing more down time than operating time and decides to move it on while the goings good or wants to look for something more reliable. The machines clock now shows 10000 hours and is 8 years old. The 4th customer could turn into a 5th or even 6th customer very quickly by now as the machine has probably been bought at a "sold as seen" auction
due to the 3rd customers choice of getting rid of a potential comeback problem. The stand about time the machine experiences in this stage of its life will greatly reduce additional hours on the clock even if the digger ages another 2 years.We now end up with a 10 year old machine with about 12000 genuine hours on the clock.
With all this in mind it is unrealistic when you see a machine advertised as 6 years old with only 2000 hours on the clock or even worse a 1988 Hymac 121 advertised with 3500 hours on the clock
you know somebodys telling lies. With many machines I buy on condition as apposed to the hours on the clock. The bum on the seat over the years has determined weather or not the machine has had a hard paper round or has been respected by its operators who have had the sence to do a bit of essential routine daily/weekly maintenance. 
I've seen machines with low hours but fit for the scap heap but equally seen old machines with high hours but have been lovingly maintained. It's swings and roundabouts but always always if it looks too good to be true it always is - common sence is essential.
. Everyone buys on condition - we don't buy bruised bannanas even if they are only a day old on the shelf 
but the hours on the clock give a realistic factual indication that should help tally up with the visual and mechanical condition. Try before you by is always a fair thing to do.
has now gone to its second home,with just over 10000 hrs on it,at 6 yrs old.During my few years with it,i put around 1700 hrs a year on it,doing a 7-5 day,with some saturday work.And my time with it was all quarry work,80 odd % hammering,20% bucket work in the quarrys.But as you know & seen from the pics,i looked after it.Ok,so it needed a bit of tlc to the pumps & track rollers,but if i had £56k,i would have been tempted.
