I've never had the same phone for 12 months in recent memory. I'm thinking the s8 will be the one I use for 2 years.
My phone history.
S8
S7
6s
S6
6
6+
Note 4
G2
5s
M7
5
Note 2
One x
Note
4s
Nexus one
3gs
3g
Treo 650
Treo 600
Dash
My phone history.
S8
S7
6s
S6
6
6+
Note 4
G2
5s
M7
5
Note 2
One x
Note
4s
Nexus one
3gs
3g
Treo 650
Treo 600
Dash