My son, who is working towards Grade 5, has been complaining about his trumpet, which is a (pre-owned) Bach Prelude which he has had since he first started learning. He mostly complains about it when he is finding it difficult to get high notes, and/or to make "clean" transition between notes, particular on big jumps / slurred intervals, so I suspect the problem may be technique rather than instrument.
However, I'm not a brass player, and don't know whether he ought to be looking to move up to a "better" instrument by now.
Any brass experts out there willing to give a view as to what level of proficiency merits an upgrade? I would ask his teacher, but he's just finished lessons for the summer , and we are targeting Grade 5 in the autumn.