A homeowner cannot tell a good roof from a bad one. They cannot judge your flashing, your fixings or whether the valley was done properly, and they know it. What they can judge, instantly and with complete confidence, is a house that looked tired and now does not.
That is why before and after photographs outperform everything else a roofing company can put on a website, and why almost nobody has them. Not because they are hard, but because the before shot has to be taken on the worst morning of the job, before anybody is thinking about marketing.
The discipline problem, and the fix
The after shot always gets taken. Everyone is pleased, the scaffold is coming down, somebody grabs a photo. The before shot is the one that is missing, every time.
So make it part of arriving rather than part of finishing. Whoever gets there first takes two wide shots before a single ladder goes up. Thirty seconds, and it is the half of the pair you can never go back for.