I see nothing to worry about at all. I agree with Dabbler that it's just old needles dropping and some ancient needlecast.
Everything else looks in prime health.
Also, I have an ick for people saying a tree needs repotting. That's a me-problem first and foremost. But I like to explain it nonetheless to maybe help put your mind at ease:
All growth looks healthy on this plant and the shoot length is A-OK. This means that it has enough rootspace to build decent structures. This means it's not root bound or pot bound at all.
A bunch of roots on the outside perimeter of the soil means the plant is exploring the limits. It doesn't mean the whole soil is full of roots, probably the contrary.
Repotting whenever because of whatever is fine! But a need differs from a want. A need is when growth stalls or your watering regime doesn't match the soil type (though that's a caretaker problem, not the soil's problem, another discussion).
Your tree can go another 4 years without a repot, for sure.
Roots on the outer perimeter of the soil can trick us into thinking the whole soil is full with them. We chop them off, dig in, and find out there's nothing left. Ouch.
With that in mind, I think it's very good that you're taking your time and waiting it out until later.
It's a nice base you have there! Can we see a close up? Is this a grafted variety that you know?