What Alicia said. If you choose the cheaper ($10 White Card) plan, you will only be able to go to your home gym. When/if you travel, you can pay (usually $5) to visit Planet Fitness in other cities. So if you travel a lot, it's definitely worth it to go with the black card plan.
If you have the black card membership, yes. It works at any Planet Fitness and allows you to bring a guest with you, every time and everywhere.
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