I'm a bit flexible on the time limit, but it depends on how nice you are to me about it and if I have another appointment scheduled right afterwards. If you're a jerk, you're leaving after an hour, and if you're a jerk who arrived late, you're leaving an hour after your appointment was supposed to start.
If a client can't get off, usually I just shrug it off, we do whatever mutually satisfying thing we can, and then I hint that they should book a longer appointment next time.
I'm not asked to dress up too often, which is good because I don't have a huge costume wardrobe. Generally, I dress nicely but not really flamboyantly sexually. A typical outfit would be a cute, flowy dress that hits right above the knee, some heels, and maybe a cardigan if it's cold out. The clothes come off pretty quickly, so I don't tend to get complicated with my outfits.