10 - 25 year old rebuilds
The 10 year Mechanical Over Haul and 25 year structural inspections serve as two points:
1. After 10 years of service whether used once a year or all year is to check and inspect whether the components in a crane are still serviceable. Saying that meaning bearing are not work and have severer back lash or that gears still have reasonable material left, additionally it is the overall inspection of components to prove continuation of service.
2. The 25 year structural inspection is again much like the 10 year inspection only that the structure itself is inspect using NDT inspections.
Both of these enforced rules have a good and bad side the bad side is they cost money and you are without plant for x amount of time. The good news is that modernization of what can often be obsolete machinery can be brought up-to and past the capability of new hoists.
For example you're hoist and crane only has a single speed in each operation with the use of VSD's crane can instantly have 2-3-4 speeds with abilities to operate at higher speeds than it previously did now while this sounds like fluff VSD's do protect brakes from wearing and the soft starting abilities also allow otherwise wearing components to wear at less than a quarter of what they otherwise would this is a fantastic advantage against normal wear and tear.
Changing over to remote controls instead of the old pendant you keep the pendant its just tied up the top of the crane.
You receive a strong reliable crane from an otherwise not so reliable machine.