One of the biggest mistakes that people do when going to WFP is trying to do the whole round 100% WFP.
I generally do patio doors and conservatories trad and the rest of the house WFP.
However if there is only one upstairs window on the back and a porch or conservatory I take the hose only as far as I have to, creep around the corner and do the upstairs and then come back and do not only the conservatory trad but also the downstairs.
Many of my house have many combinations, some are all WFP and others have some trad thrown in especially on the backs.
Do what is best for YOU not your customers, save time and water by allowing trad to have a role in your business but allow WFP to tell YOU what will help get your round done quicker and more efficent.