I see loads of moth damage where I am and your right the customers mostly don't see the value in getting it dealt with.
i had a customer call me up and tell me they had a problem and that they had eaten her cashmere jumper, after a conversation i gave her the price to clean and treat, her "really, that much!" me " how much was the cashmere jumper?" her " yeah your right, when can you come and do it?"
Another I did this week but i told her 2 years ago when i cleaned her four bedrooms, she didn't want the stairs doing because it was brand new carpet, the place was absolutely crawling with them and i suggested she sort the problem before they damaged her brand new carpet but to no avail. Treated it this week but it was completely destroyed.
Tony