A USB hub's port count is the easy, visible spec — the more important, less obvious spec is how much total bandwidth and power those ports actually share.
Total bandwidth is shared, not multiplied per port
A hub or dock connects to a computer through a single upstream connection with a fixed maximum bandwidth, and every port on the hub shares that same total bandwidth pool — plugging in more devices doesn't add more bandwidth, it divides the existing bandwidth among more connections. Running several bandwidth-heavy devices simultaneously (an external monitor, a fast external drive, and other peripherals all at once) through a single hub can create a real bottleneck that wouldn't exist if those same devices were connected directly to separate ports on the computer itself.
Power delivery wattage determines what it can actually charge
Docking stations and hubs that claim to charge a connected laptop have a specific power delivery wattage rating, and this needs to meet or exceed what the specific laptop actually requires to charge at a normal rate — a dock with lower power delivery than a laptop needs might still technically provide some charge, but can mean the laptop very slowly loses charge during heavy use even while "charging," since power draw exceeds power delivered. Checking the specific laptop's charging wattage requirement against a dock's stated power delivery output avoids this mismatch.
Video output support varies more than expected
Not every hub or dock supports multiple external monitors, and among those that do, actual supported resolution and refresh rate combinations vary — some docks support two 4K monitors at full refresh rate, others support the same monitor count only at reduced resolution or refresh rate. Checking a dock's specific supported display configurations against the actual intended monitor setup, rather than assuming "supports two monitors" covers any resolution or refresh rate combination, avoids a real, sometimes disappointing surprise after purchase.
Chipset quality affects reliability more than the number of ports
Two hubs with an identical port list can behave very differently in practice depending on internal chipset quality — cheaper, lower-quality chipsets are more prone to random disconnections, driver conflicts, or devices failing to be recognized consistently. This is difficult to assess from a spec sheet alone, making real user reviews specifically about reliability more informative than the port list for anticipating how well a specific hub will actually perform over time.
The one thing people forget
Check cable length and desk setup compatibility, particularly for a dock meant to sit at a fixed position on a desk with a laptop moved in and out of place regularly — a dock with a very short built-in cable can be awkward if the desk layout doesn't naturally position the laptop close enough, a practical detail easy to overlook while focused on port count and specs alone.