Do you always buy your new phone a case?  

Usually yes. I am pretty protective of my phones, and most of the time I do buy a case. The only time I don't, is when the phone comes with a case, or it's already pretty well protected. 

I never used to because I didn't see the point. Most of them do little to nothing to protect the phone. That being said, as smartphones became sleeker and thinner, I found it hard to actually grip them well and started buying cases. I will usually buy 2 or 3 I like and swap them out every few months. 

I tend to stick with the same phone for a while so when I do get a new one, I usually get a case if it doesn't come with one. I just like to have that added layer of protection.