Who I have the same questioned this topic

I currently have an iPhone 5s and plan on purchasing a new iPhone 7 or 8.

I would like to know the details of swapping the SIM card.

I kayak and would like to take the old iPhone 5s when I do so.  Is it as simple as just taking the SIM card out of the new iPhone and putting it in the old 5s?

If so, is it adviseable to do this?  Do I risk wearing out the receptacle buy removing/inserting the SIM card repeatedly?

Thanks