Yes, you do.
Because you know, apps have a tendency to be updated. And developers don’t want to support old APIs.
So if you wanna use new apps (new versions of them), you update your phone.
Nowadays phones don’t exist in a vacuum using only GSM standards, otherwise I’d still be using my beloved SE P900i or N9.
So it’s pretty normal to use Xx for 4 years and then update to 10mk3.
I’d even say it’s environmentally friendly.