On the fitting side I usually do 2/3 of these a month.
The ones I get called to look at are way beyond cleaning, bonded insert being the only option, if the custi has any spare.
Jute backed tufteds or wovens with a cotton chain warp are by far the worst as the backing disintigrates further than the face fiber as the moisture spreads out sideways underneath, requiring a bigger patch than you might expect.
With more action backed coming on stream I would expect this to reduce over time.
Usually I heat seam 3 sides and use scrim tape and a hot melt glue gun on the forth.
Half of them look crap, to me the other half ok though the custi's seem happy enough.
For some time I have been thinking about importing one of the new coolglide seaming irons from the US which uses microwaves to melt the adhesive through the face fiber rather than a traditional seaming iron which goes between the tape and the carpet backing.
These new seaming irons would be perfect for this type of repair as there would be no problem with iron runout
I don t think anyones got one here yet so I would be the first in the UK