Notification mirroring, sleep tracking, step counting, a bright always-on display, and a battery that lasts more than three days.
What to skip
Blood pressure and blood sugar readings on cheap watches are not medically accurate. Treat them as a rough trend only.
Water resistance rating actually matters
Look for at least an IP68 or 5ATM rating if you want to wear it in the shower, in the rain, or while washing your hands without thinking about it. A watch with no stated rating should be treated as "keep it dry."
Check phone compatibility before you buy
Many budget smartwatches are built primarily for Android and lose features — or app support entirely — when paired with an iPhone. If you're on iOS, confirm the watch's companion app is actually available and fully functional for iPhone before ordering, not just "compatible" in the fine print.
The always-on display trade-off
An always-on display is genuinely useful — no more flicking your wrist to check the time — but it's also the single biggest drain on battery life. A watch advertised at "7 days" typically means with the always-on display switched off. Decide which one you'd rather have.
GPS matters if you run or cycle outdoors
A watch with built-in GPS can track distance and pace accurately without your phone in your pocket. Watches without it usually borrow your phone's GPS instead — fine for everyday use, but it means leaving your phone at home isn't really an option if you want accurate outdoor route tracking. Battery drain from GPS is also real — expect a GPS-tracked outdoor session to cost noticeably more battery per minute than everyday notification use.
Strap and charging
A proprietary charging cable or dock is easy to lose and hard to replace outside the box it came in. If you travel often, a magnetic USB-C charger is far more convenient than a dock you have to carry separately.