Continuity mistake: In Season 8 - Threads, when Sam is talking to Jack in his backyard (barbecue scene), the back door behind her opens and closes between shots.
Continuity mistake: Jacob Carter repeatedly mentions blending with Selmak 4 years ago, placing it in Series 4 (each season constitutes a year - when Carter leaves the SGC to join Atlantis at the conclusion of season 10, she talks to Teal'c about how they have spent 10 years together). However the blending occurred in Series 2 (6 years ago).
Answer: While the series was undeniably successful, filming it is a long process, taking many months of often long days. Anderson, after several years of doing this, wished to spend more time with his young daughter, who he felt he was neglecting, and requested that his role in the series be scaled back. Ultimately, he decided to leave the main cast altogether and only make occasional guest appearances.
Tailkinker ★