As has been said on 4 or 6 weekly repeat cleans there's very little to remove from the glass other than a small amount of dust and so on (that's why I laugh at the hot and snake oil users ) but in reality what slows us down tends to be things like degraded powdery frames, leaky openers, degraded rubber seals, leaded windows, problem vents and so on which take different slower methods to get right, the time you spend trying to get perfection on these will depend on pricing.