This Old House is celebrating 35 years on public television, while the TOH spinoff show Ask This Old House celebrates 300 episodes. After all these years of teaching YOU, though, even our skilled professionals learn a thing or two while shooting. Here are their top 10 home-improvement lessons. -Tabitha Sukhai, thisoldhouse.com DID YOU KNOW: You can catch full episodes of TOH and ATOH online? No charge.