Fully agree with LittleInch.
You need to define: Location (offshore/onshore/chemical/water treatment/pharmaceutical/etc.)? type of valve(gate/globe/check/BV,etc)? Was it due to worn out but still movable obturator or completely stuck? Dirty or relatively clean internal? Which trim (only obturator + packing or with seat(s))? Is drawing available? Is spare part available? Is pre-work count (scaffolding, breaking the bonnet, permit issuance and decontamination)? Pressure test included? Certain leak tightness required? Special tools required? and will it be done by general experienced contractor (Jack of all trades) or manufacturer representative?
If it is dirty or been years in service, please expect some ingenuity to even remove the old parts.
People often mistaken that most of the time for trim replacement is not ‘Plug and Play’ shall be installed on existing body. Even if those trim came from same batch. Some cleaning, tweaking, and lapping often required. The bigger the valves, more time is required.
Manufacturer representative often only send their technician(s), which in the event of unexpected circumstances, usually further consultation with engineering department is required. This will add extra time as well.
And above are only some of the factors that I can think of, there are more.
Been in 30 minutes spectrum usually for small, clean and well-engineered valves, and even 3 days when trim might not fit (due to deformation inside body) and/or re-engineering required..
Regards,
D