In the near future I will be looking for a 4 Axis CNC milling machine and a 2 Axis CNC lathe. Both will need to have repeatable accuracy in chromoly stainless steel and Titanium. The easy bit is knowing what capacities and capabilities I need them to have, the hard bit is knowing whether to buy new (horrendously expensive) or second hand (lower price but reliability and remaining precision unknown).

If I was comparing a new or second hand car, well I have the experience to judge how age and mileage will effect the functionality of a used car and work out if it is still fit for purpose, but I don't have this knowledge for commercial CNC machines. The price difference between new and second hand is a lot and buying new will dramatically increase the time it takes to get my startup company into profit. On the other hand buying a second hand machine that was constantly breaking down or had lost its repeatable precision would be pretty dire. I appreciate this may well be an impossible question to answer but it'a still one I need to ask

How do you judge the effective lifespan of a commercial CNC machine? I realise I can rely on the advice of the various companies that deal with second hand machine tools, but I have no way of judging whether their advice is similar in quality to that of some second hard car dealers

Can anyone recommend a trustworthy firm or failing that give me some general guidelines?
Best Regards to all
Sarah