How long should a side-sleeper pillow last before it needs replacing?

Verified-purchase reviewers and r/BedroomBuild threads suggest 1–3 years is typical for foam pillows before noticeable break-down, with shredded-foam pillows lasting longer when you top up the fill. Down-alternative budget pillows like the Beckham are widely reported to flatten faster, which goodhousekeeping.com's testing also flagged.