Cleaned my own windows, in and out, in the low sun today and they looked immaculate.
I did take my time though as was trying to get out of the hoovering.
The longer you spend scrubbing and rinsing, the better the results, in any light.
Obviously when your out working though time is money so your trying to get through everything that bit quicker, and can quite easily miss small sections of glass without realising.
Vision helps with that
