- If there's any cost at all attached to shop alterations, I always have them done by my own tailor instead.
- If the shop is covering the cost of alterations, I typically hem & haw for five minutes, and then decide to have them done by my own tailor.
The underlying issues is that it's much less hassle to go to the same place for all your alterations. You know them, they know you, you know what you're getting and they know your preferences. It's just so much simpler all round because everything is a known quantity and there's no game-playing. The more important thing IMO is learning not to buy RTW unless you know what can and can't be done at a cost-effective price for you. Because of this, I personally prefer not to get RTW unless I know that all it needs is something very minor; in practice, that means just trousers in terms of tailored items.