Completely random thought; James Horner repeats himself a lot.

I've noticed this while watching films with score by him. His Aliens score has the Klingon theme from Star Trek III in there, and his Apollo 13 score just sounds like an amalgamation of all his previous scores. Titanic is one musical theme repeated over and over ad-nauseum.

Rest assured, I mainly only like his two Star Trek scores, as they're both very different from each other in terms of themes.

Of course, Leonard Rosenman was prone to this as well (He used the same theme for the apes in Beneath the Planet of the Apes and for the wraiths in The Lord of the Rings.)