Enlarging the font size on your phone is one of those famous old-people tech habits, like putting "..." all over your texts, or posting Facebook memes about sauerkraut. But it's healthy for younger people too — it reduces eye strain, according to Intelligencer.
"You're focusing for so many hours that your eyes are relaxed when the font is bigger because your lens does not have to focus as strongly in order to read larger print," ophthalmologist Saya Nagori tells Intelligencer. If you use your phone a couple hours a day, that's a lot of focusing. Squinting at text doesn't permanently degrade your vision, but it does make your eyes feel more tired by the end of each day.
If you won't do it for yourself, at least help out your parents, who might not even know how to enlarge their text. On iOS, open Settings, select Display & Brightness, then Text Size. On Android, it's Settings > Display > Font Size.
A larger font does not feel cool. But it's smart. Phone screens keep getting bigger, so take advantage of that extra space and enlarge your text. You're not getting old. You're just growing up.