@SugarCubes posted the general maiden, novice, and limit rules. There are is a different set in the Equationâ>Hunt Seat Rules, that reads as follows EQ 110.4):
4. Maiden, Novice, Limit, Intermediate. Open to riders that have not won one/three/six/twelve first place ribbons respectively competing in equitation classes at Regular and Local competitions of USEF or Equine Canada. a. Maiden. For juniors and amateur riders who have not won 1 blue ribbon over obstacles.Test 1 b. Novice. For juniors and amateur riders who have not won 3 blue ribbons over obstacles. Tests 1-7. c. Limit. For juniors and amateur riders who have not won 6 blue ribbons over obstacles. Tests 1-7. d. Intermediate. For juniors and amateur riders who have not won 12 blue ribbons over obstacles 3â3" or higher. Tests 1-12. e. Open. For juniors and amateur riders. Tests 1-18. f. The Maiden, Novice, Limit and Intermediate status of riders at Regular and Local Competitions is determined from the closing date of entries. Blue ribbons won in the Hunter/Jumping Seat Equitation section will not affect a riderâs status in the Saddle or Stock sections, etc. Ribbons won in classes restricted to a particular breed will affect a riderâs status. Ribbons won as a junior affect a riderâs status when competing as an adult. g. Ribbons won in leadline classes and in classes where entries are not required to ride at all gaits will not affect Maiden, Novice, Limit and Intermediate status. h. Ribbons won in classes not to jump do not affect a riderâs status in classes over jumps. However, ribbons won in classes over jumps do affect a riderâs status in classes not to jump. Ribbons won in classes with less than six (6) entries do not affect a riderâs status. Ribbons won in short stirrup classes and in classes over obstacles lower than 2â3" will not be counted in reckoning Maiden, Novice, Limit, Intermediate or Open status.
if you find that screen dump unreadable, hereâs a link - https://www.usef.org/forms-pubs/XdvTAt99tBw/eq-equitation-division
So itâs quite possible to be pretty accomplished and still be officially limit at a USEF show.
My recollection is that HITS followed the normal rules for junior eq, but for adults had a variety of divisions at different heights, slapped on some cross-entry restrictions, and let the adults sort themselves out.