My dd was training L10 last summer, and she missed quite a bit of time in July. Our gym was closed for a week, then she was back for a week, and then we were gone for almost 3 weeks on vacation. It was the first time that we had been gone for more than a week, and I would not do it again unless she could practice at another gym, because her coach thought it really slowed down her summer progression. Not just figuratively slowed down, but literally - I was told she came back tumbling like a turtle. So, we'll take a few long weekends this summer.
For those that have practiced with other teams, do you contact them directly, or does your coach do it? Do you ask your coach for permission? I just can't see ours being ok with dd going somewhere else and her not knowing about it!