Headphone shopping gets complicated fast because "sound quality" is genuinely subjective — but the physical form factor, battery life, and how noise cancellation actually works are all things you can evaluate before you buy, not just after.
The three form factors
Over-ear cups fully enclose the ear. Generally the most comfortable for long sessions and the best natural noise isolation, but the least portable.
On-ear cups rest directly on the ear rather than around it. A middle ground on portability, but can feel less comfortable over long periods since they press against the ear rather than surrounding it.
In-ear (including true wireless earbuds) sit in or at the ear canal. The most portable and the best for exercise, but comfort and fit vary the most from person to person — the included ear tip size matters more than most buyers expect.
What noise cancellation actually does
Active noise cancellation (ANC) uses microphones to sense incoming sound and generates an inverse sound wave to cancel it out, on top of whatever passive isolation the physical design already provides. It's genuinely effective against consistent, low-frequency noise — engine hum, HVAC systems, airplane cabin noise — but far less effective against sudden or high-frequency sounds like voices or a baby crying. If your main goal is blocking out a specific kind of noise, it's worth checking what that noise actually sounds like before assuming ANC will handle it well.
The spec people underweight: latency
For music and calls, small delays between audio and what's happening don't matter. For watching video or gaming, noticeable lag between the picture and the sound is genuinely disruptive — and it varies a lot between wireless headphones depending on the Bluetooth codec and chipset used. If watching video or gaming is a big part of how you'll use them, it's worth checking reviews specifically for latency, not just battery life and sound quality.
The one thing people forget
Check the actual charging case battery life for true wireless earbuds, not just the earbuds' own battery life advertised in bold on the box — the case's total capacity is what determines how long you can go before needing a wall outlet, and it's often buried lower in the spec sheet.