How often do you guys replace your smartphone?

I kept my LG Optimus Fuel for 15 months, until it started acting up and not working in November. I then switched to a LG Lucky, I hated it and kept it for a week. I then switched to a LG Optimus Dynamic II. It is an okay phone. But I found a Moto E on sale for $20 and switched to that on Sunday. I like this phone and bought a back up. This will be the phone I use until it dies. I then have a second Moto E that I will use.
I purchase a lot of Net10 smartphones on sale or clearance for $20. So for $20 I can afford to switch my phone when ever I want to.

Only rich people afford to replace phone that often. haha

It maybe has been less than a year this time but that phone replaced my S3 that I bought before S4 came out. The only reason I am replacing my Oneplus One is I need on of three Nexus models to try google fi. So now it tends to be when I switch phone companies or wear out a phone,

it used to be every two years that i believe most companies gave their customers a large discount on phones to sign a new contract for another two years but thats changing a lot now so my answer was every two years if I had a discount available

Generally every two years, although my current one is approaching three and I'm going to try to push for four.

The only reason I have one is because my stepdad upgraded and gave me his.

This was like 3 years ago, though.

My cousin frequently "loses" his, so my stepdad has given him his hand-me-down for the past few years now.

Every two years