I don't care what anyone says about this job, it's DIFFICULT!!! I've finished one out of six frames on this boat. On mine, there wasn't one fuzz track where there was an access opening on either end to slide the old out and the new in, unlike all of the drapery tracks where you have to put a set screw in place to keep the drapes from sliding back out. Each frame takes three pieces - two pieces of glass and one screen for a total of SIX perimeters of fuzz around that entire frame. This is why some folks say they've done ONE window and to hell with the rest. While I understand how folks got to that mindset, I'm trying not to fall in that category, but that said, I have ONE frame done.

And the rest are not on my short list of to-do's.
Tools Required (removal and re-installation):
Needle nose pliars
Nine different size/shape metal dental picks
Tweezers
Small flat-head screw driver
Heat gun (for the glides)
SailKote (LOTS)
Razor blade
Dremel tool with a cutting wheel
Small hack saw
Advil
Adult beverage of your choice (more than the amount of SailKote)
Patience (more than the amount of adult beverage and SailKote combined)
IPOD with 1,118 songs loaded so you don't feel so alone - no one wants to stop by for fear of being asked to help.
I had to sit on that 1/8" thick (or less) strip of metal (bottom part of the frame, as shown in Sky's photo above) for about an hour leaning backwards over the water in what felt like the world's longest sit-up, working on getting enough of the glued-on metal pull cut and removed so I could get the window out. I won't begin to describe how sore my affected body parts are for that one! Last time I tried to use the putty knife to slide in between the metal pull strip and the glass, I broke the glass - now, I cut the top 1/4" off the pull with a Dremel cutting wheel.
Ahead of me...five more frames, each with three tracks (that means six rounds of friggin fuzz), and on one of those windows, some bonehead epoxied the window in place thinking that's how you fix a leak. IDIOT! Window still leaks. 'Cuz that's NOT how you fix a leak, not in a window, anyway.
I found that it was easier to install the fuzz (not that it was easy by any means) before you install the glide and then just run one of the dental picks along side of the glide to lift the fuzz back up over the glide. I had both scenarios, and hands down, the fuzz was harder to install after the glide was in place. For me, glide goes in last.
As for the suggestion to replace these every three to four years. NO WAY!! will I bite of on this again in just a few years! These lasted 28 years, and in 28 years, the stuff I'm installing today will still be there! I will finish the other five frames because they need doing (though, I haven't said "when"). After that, if it needs doing again...time for new windows.
So, now you know how I really feel about replacing window fuzz and glides. I will admit that the windows do slide so much better with new glides underneath them.