2 Garmin watches...

Has anyone used 2 Garmin devices together?, Not at the same time but say one for recording activities/training and the other when not doing an activity/training. Just wondering how a Fenix 5s and Forerunner 935 would work together without losing accumulated data from each watch , 935 for training and 5s when not. I like to keep track of my steps (yep sure do) and wonder say after working out with the 935 what would happen when I go back to the 5s. I didn't lose anything when I initially swapped out the old watch to the new watch but doing it at least 5 times a week how things would turn out. I know I still have my 735xt listed on my main page on connect.garmin but have not used it since going to the 5s then to the 935. I'm missing the look and feel of the 5s sapphire (935 is no slouch in the looks department but...) and going to get another 5s sapphire. I also use the Stryd footpod and had crazy dropouts with all the watches but it was rectified by a replacement pod and now I have almost no dropouts on my 935 and hoping to get lucky with another 5s and maybe the Stryd pod will work with the 5s and if that's the case then it'll be the 5s all the time. Just wondering if anyone is doing this or if anyone would be kind enough to share their opinions or experiences (we all know about opinions but they can be useful too :) . )