Reel bearings
A bearing sits wherever one part turns against another. A reel has several such places: the handle shaft, the rotor shaft, the oscillation gear, the line roller. Each bearing is one such place, no more and no less.
Why the count proves nothing
The number on the box counts places, not quality. Nine cheap bearings do not make a reel better than four good ones, and some of those nine can be fitted where there is barely any load at all.
Two reels cannot be compared by that number: it says nothing about the material, nothing about sealing, nothing about how long they will last. It is a specification that is easy to print, not one your hand can feel.
The line roller works differently
Every other bearing is turned by your hand. The roller is the one place where the line itself rubs against a part, and rubs under full load: everything the fish pulls passes across it.
If the roller does not turn, the line runs over stationary metal and cuts a groove into it. That groove then saws the braid on every cast — and the commonest cause of a sudden break is here rather than in old line.
Bearing or bushing
In a cheaper assembly a bushing takes the place of a bearing — a plain sleeve with no balls in it. It is quieter and cheaper, but there is more friction in it and it wears out sooner.
Swapping a bushing for a bearing is done first of all on the roller: that is where the gain shows on the water, not merely in how the handle sounds turning in the shop.
The one-way clutch is a bearing that holds
One item on that list works the other way round. The one-way clutch is a bearing whose rollers wedge when it turns one way and run freely the other. It is what stops the rotor from backing off when you strike.
Its wear shows at once, and in that too it is unusual: the handle starts giving back a fraction of a turn before it picks up. The other bearings fail quietly, this one audibly: its condition is visible without stripping the reel, from the behaviour of the handle alone.
What destroys them
Water on its own is nearly harmless; what destroys them is water with sand in it. Sand gets inside with the spray and on the line, mixes with the grease and turns it into a paste that works as an abrasive.
Hence the first rule: a reel is never submerged and never hosed down. The routine is set out separately — reel care and storage.
What we do not state here
How many bearings a reel ought to have, and after how many trips they should be replaced. Both depend on the design and the conditions, and we found no verified source for a general answer. The sign that needs no number is grinding and play: once it goes rough or gains side movement, it is time.