I answered the survey, but - I generally manage cell phones for 3 of us. We have swapped phones around in the past, and continue to do so. I hang onto phones for a while, sometimes re-purpose atypically. Currently, one old phone is a streaming camera to go with our weather station. One old phone is used for audio books in the car when we're travelling. That way anything I'm doing on my phone doesn't wind up interrupting the audio. The car I used to drive to work had a USB port and you could plug in a flash drive, but the phone is more flexible..
We use Google Voice numbers, which offer great flexibility. Coverage for any carrier is lousy at our home, so we have Voice ring the VOIP house line as well. That also offers the utility of multiple wireless handsets, instead of shlepping the cell around and leaving it where you aren't anyway. GV won't port in our landline number.
I'll also add that I used Google Fi for a while, worked great overseas, but data bills were too high either at home or away. Google Voice, with a foreign SIM when traveling overseas, has also worked for us.
The most recent upgrade in the household was partly to take care of hubby's dying battery, paid cash for fully unlocked phone, and partly to get a 'new customer' plan for him (on Sprint) that seems like a good deal for him.
We used Ting for several years, still like the concept, but often ended up with what we felt was a high data/text bill, and we don't stream music or movies on our phones. I would like it if Ting would sell data the way Total Wireless does. Right now I have their cheapest voice/message plan ($23.70 with auto-refill) with add-on data that doesn't expire - $10 for 5GB, and you can add more than one 5GB bucket at a time if you want. So I'm pre-paying data buckets that get used at will. When we're around home, we can easily use wifi hotspots, but when we travel, our data usage is higher.