What's the best age to do a working holiday visa?
Do it before you turn 30. Most working-holiday visas — Australia, New Zealand, Canada — cap first applications at 30, with a handful of countries stretching to 35 for some nationalities. Your early-to-mid twenties are the sweet spot: you're eligible almost everywhere and have the fewest commitments to leave behind.
Age limits are counted at the date you apply, not the date you travel, so if you're close to a cut-off, get the application in. A few schemes (parts of Australia's programme, Ireland, and others depending on your passport) run to 35 — worth checking your exact nationality against the destination.
Beyond eligibility, younger tends to be easier: fewer ties, more appetite for casual and seasonal work, and more time to make the second-year extensions (like Australia's regional-work requirement) worthwhile.