Just wondering
TIA
just before you plough into a tree. 🙂
In all seriousness. it can be a time thing, or a feel thing.
If the lever is consistent, each time you pull it, it works the same, then you have no air in there.
What does happen over time is little particles get through the dust seal and 'contaminate' your fluid ever so slightly...
However saying all of that, your brakes are a sealed system... if sealed perfectly there's no reason you ever need bleed them.
Spongy and inconsistent feel for me.
annually or if the go spongy. DOT fluid brakes its particularly important as the fluid absorbs water and drops its boiling point
As long as they feel right, leave 'em alone.
First step for troubleshooting a brake problem for me is always to bleed it. If that doesn't fix it, buy a new brake 😉
Leave them well alone unless they feel spongey.