That sums it up very well.
I've restored a few machines and my buddies have done more, mostly for ourselves as we search for our ideal machines but including a couple of overhauls for people who asked nicely.
It's never as simple as expected.
The machine is always worse than the owner describes
Parts are expensive to source and/or need access to a full machine shop to take stock parts and machine them to fit.
If you work on your own machine, even if that is one you ultimately sell, you are in charge and the decisions on what to do are all yours.
If you work on someone else's machine against some sort of estimate of costs, it is frustrating because working to a budget, you have to leave things undone because the owner won't value the little things enough to pay what it costs to sort them. You waste time and energy working around problems but still trying to get the machine just right
If you break the machine, it's on you. Lots of risk, the pressure of a deadline and little upside. Nah, not fun.
I recommend good old machines to people because they tend to be well built and long lived, but unless you have some mechanical aptitude and are willing to learn how to maintain them yourself, you may be best off with cheaper machines and consider them disposable because no one will fix them either once they are out of warranty.
I'll offer a view and would be interested in readers comments.
What is the going price of a repair to fairly expensive kit ?
It isn't unusual to find a repair costs maybe half of what something is worth. More than that and you start to query whether the repair is worth it or should you just pay more to get a new machine with a full warranty.
Sedgwick machines are typically £4k plus new.
So if a repair cost £2k, that's not atypical, yes ?
If you could find someone to restore your machine (not me), would you pay that or would you take your money to Axminster and buy a new Harvey ?
Sedgwick charge a lot for their spares. It has nothing to do with what they cost them. It has everything to do with how much they can get out of you.
Fortunately what usually goes wrong are bearings, bronze bushes, motor bearings or even whole motors, rubber belts and the like. You buy all of those at affordable prices from the online bearings and transmission suppliers.
You assess your machine carefully and in the worst case you also have to give Sedgwick £200 apiece to replace a couple of worn out sprockets and you buy a new drive chain from someone else.
So if you DIY, you might get away with between £150 and £750 cost of parts to bring a machine back to full working order.
Just don't drop anything important or the cost of one big part will be more than your whole machine is worth.
Good luck