Younger men are always going to be more physically appealing to the vast majority of women, that's just the world we live in, but this is a business so you have to understand the decisions a WG makes on age based upon that fact.
Younger men are more volatile, will tend to be less well behaved and less respectful, all of this spells danger to a WG, not to mention that they may not have good personal hygiene. Also, the likelihood of getting 'extras' such as presents, tips and an 'easy ride' in terms of the sex itself is dramatically reduced when dealing with men from 18-30.
Older men are more polite, more financially secure, and are more likely to be set in their ways, meaning a much higher chance of repeat business, they will also have less stamina. From a WGs point of view, an older guy is preferable to younger.
None of this has anything to do with physical appearance. If WGs cared about what men looked like, they wouldn't be doing the job. You can be 25, great looking and have a body like Adonis, but you aren't going to light up a WG's eyes like an old fat dude with a wallet full of £50s.
