In general, the United States has tended to make expensive aircraft with long service lives. The Soviet Union and later Russia has tended to make affordable aircraft with short service lives and higher maintenance requirements. Some Russian fighters, such as the earlier Su-30 Flanker, have also suffered from significant reliability issues.
The Su-35 appears to narrow the gap in this regard somewhat—it is supposed to last six thousand flight hours. The F-15C and E are rated to last eight thousand and sixteen thousand hours, and the former is likely to undergo a life-extension program. On the other hand, the Su-35s rolling off of factory production lines will be at the beginning of their service lives, while most F-15 airframes date back to the 1970s and 1980s.
