We mustn't forget that trad work will often leave small smears after detailing, or lines from the squeegy when detailing not carried out, or more general smears if you are having to polish with microfibre or scrim.
You think you have done a good job (just as you will with WFP) but then the sun falls in a certain way at a certain angle that highlights these errors.
I agree that if you study the glass closely after it has dried out, on at least a couple of windows you'll find the odd row of little dots.
But you will also find mistakes if you check out your trad work, probably only tiny ones if you are good at what you do.
how often have you done the outside and the customer has asked you to do the insides...only to find you have to pop back outside to pick up on the odd mark or run etc??
I'll also agree that in general, WFP is less consistant than trad by the way.
But I picked up a job that was done previously by a team I know well, and they are good window cleaners too, but they are 100% trad.
They had obviously been rushing, not bothering to detail when they should have done, customer complained about the lines around the window frames, which wouldn't have been there if they had detailed.
she also complained about the state of her frames too, as they never bother to clean the frames, the cobwebs and spider nests had built up to a high level, so even when they cleaned the glass properly, the windows still looked shabby.
As you work your round you learn the windows that aren't suitable for WFP, some you'll never get right, well for me, if they are upstairs then tough, it's like it or lump it cos I won't work off ladders, but I will trad any downstairs windows that just won't come up right with WFP.
Actually, I'll still do them WFP, but I'll nip over them with my squeegee when I've finished the house.
Ian