Buy to the bed length: simple, one or two long bars, done. Buy to the bend length distribution: look at what actually ran over a quarter, build a ladder of segments around that.

The arguments I hear for segments:

Build the length the part needs instead of running a 3 m bar for a 300 mm bend.

Leave a gap where a clamp, a holder or an already-formed flange sits. On a solid bar that obstruction decides the setup for you.

Handling. A 100 mm segment is lifted by hand; a full bed-length bar isn't. Safety and changeover time in one.

Damage containment. Damage a segment and you replace a segment, not a 3 m bar.

Two things I'd like real-world input on:

The ~12.5 kg threshold on Trumpf/Wila style. Under it, segments use the spring-loaded fast-change button on the front face and go in by hand. Over it, side locking pins or studs into the ram's hydraulic clamping. Has anyone been bitten by ordering the wrong retention for a segment's weight?…