It can be a PITA but as mentioned above it’s not something you do every year. I’ve done it once on my 3 year old mountain bike. I ordered the headset bearings then realised I needed new olives for the rear brake as the hose wouldn’t come through the frame without cutting the end off. So all in I needed a replacement gear cable for the rear mech, An olive for the rear brake hose and replacement DOT brake fluid.
It took a few hours to strip out, then fiddle about getting the top headset bearing installed with the hose and cable outer through it, the lower bearing was as a normal instal and it was also a bit of a pain re cabling and re installing the hose through the frame. Then of course rear mech indexing and refill and bleed the rear brake line. £80 is a great price for a bike shop to do it.