Best I've ever used it the Tesco clear spray.
84p and not a smear in sight.
why use a spray when there is no need 
?? 84p is expensive if you dont need it in the first place
84p is cheap, not expensive at all, and you also get a sprayer.
If you buy a sprayer by itself it is over a £1.00, and it will wear out just as quickly as the one that comes with the 84p tesco's jobbie.
I'll also water the solution down as I slowly use it too, so it goes quite a long way.
A dab or a quick wipe down the middle of the pane of glass with your applicator is also effective, however...don't kid yourself that you won't leave smears behind at times!
I do use this method at times too, have done for donkeys years and in most instances it is absolutely fine, if there are smears left you can't see them,, but if the lighting is right, like a low level winter sun, they will show up.
A specialist glass cleaning solutions, coupled with a microfibre cloth is the best combination for that method.
Mind you, I will also use a clean microfibre that I have sprayed with pure water, get it to the right level of dampness (just barely damp) and on repeat clean (internal of course as I'm WFP) you can use just that and nothing else.
I've also sprayed a microfibre (or a scim in the old days
) with window cleaning solution, slightly more than damp, then clean with that & buff with a dry microfibre, that works great too.
I had a house last week, a really big Georgian style mansion, flew around the outside in 40 minutes with WFP, it had been re-painted, all huge Georgian sash windows and it came up fantastic.
The guy had only moved in there 2 months ago, prior to that the previous people had not had the inside cleaned for a couple of years....
Spray and buff?
?
Not a chance, every single pane had to be fully washed with applicator and most of the frames too
pre-detailed and then squeegeed off, and mostly having to be detailed again to finish
The inside took me 3 and a half hours!!
So there are times when a spray solution or wet cloth/dry cloth simply will not do.
Oh, might have taken me just over 4 hours in total, but for £120 it wasn't too bad, and next time it will take about 2 hours for the inside (that's 60 BIG georgian windows by the way)....
I use whatever method is best for the conditions and I've no doubt I'll keep experimenting and trying new variations as I go along.
Ian
