Swapping T-Mobile sim

[d3sl91]

I have an LG-G4 and an iPhone 4s (and likely going to have another cheap phone in the future). 

 

I plan on using the iPhone at the gym/traveling/hiking etc, where I don't want to bring a big/expensive phone. So, I just want to swap the sim when I want to use the iphone. 
I have never swapped a sim card between phones, other than to upgrade. Anything I should be concerned about? 

 

UPDATE:

Also, another question - I have a Tmobile sim for my tablet as well (data only, 2GB/mo etc). Should I be able to put that into the iPhone and have data only? 

[connor201]

you should have no problem switching a tmobile sim between phones the data only sim may not work at all. I switch between my LG stylo and my Iphone 5s depending on what i am working on or if i need to test something. Those i do not think that those two phones have the same size sim card.