If you can hold onto school friends throughout life, then that is always nice. You can always think back on the memories even if you didn't have a phone to take pictures in school.

I didn't really keep any of mine and did catch up with a couple, sometime into adulthood but they really weren't very good or made any effort.

The only phone I had in high school in 2003, was a Nokia 3315 and I bought it with money earned, doing a heap of work experience for a local electronics company.