My FSA orbit headset is a bit crunchy and I've got my eye on a nice new King.

Is it a DIY job to replace a headset or do I need to take it to a shop to get it fitted?

TIA

I get a piece of copper pipe, cut so far down it with a hacksaw, Flare the end and knock it out with a hammer.

Then use a few washers and a bar to pull the new ones in

Well… It's an Orbit, so the cartridge bearings are replacable and I think can be bought easily from CRC. So, unless you really want to upgrade to a CK which is really no better, there's no need.

But, if you do want to sidegrade for the same of bling 😉 Then It's DIYable but not the easiest. You can fit a headset with only a screwdriver, a hammer, a bit of wood and a rubber mallet but it's not good practice, and easy to **** up- I've done it on my own bikes but I'd never do it on anyone else's, I'll tkae the chaince with my own kit.

A headset press is the right tool for the job and they're expensive to buy. I built one myself out of some wood, some bits of scrap steel and an M10 threaded bar, some washers and a couple of bolts, took about half an hour and cost about £2 but not for everyone I think.

It's one of those jobs that often just makes sense to get fitted professionally, take them the frame and forks already seperated and it's a super-fast job.

Get hold of the proper tools or get your bike shop to do it for you.

IIRC CK strongly recommend getting the headtube faced so the upper and lower races are parallel – I imagine the argument *may* be that there's less slop in their bearings and so the fit's more crucial. Tho' a lot of bike shops probably don't bother facing headtubes either, unless you ask.
(Or mebbe they do, since it's common now to face BB shells for external bearings..)

personally knock the cups out with rubber hammer and crow bar
Knock the cups in with rubber hammer and wood.

Not really sure what can go wrong but its agricultural approach is not for everyone.