[Closed] Changing the movement in a quartz watch - how hard can it be?

So the beloved titanium Seiko has finally given up after about 20 years of abuse including getting water inside and being dried out with a hotel hair dryer. I like my watch and all the scars and wear and tear and want to replace the movement; my local jeweller wants £80 to fit a new movement, which is what the watch cost me. Is it as simple as finding a replacement then fitting it? What about the hands? I've seen Seiko movements on Ebay but they all mention trimming the spindles or posts or whatever.

I changed the battery in my original iPod Nano but that was a nightmare job I never want to repeat.