I have used a few second hand phones and they've pretty much always been fine fortunately. I see it could be a bit of a risk, but if the initial cost is so much lower, does that factor in to lowering the risk too? If I get a second hand phone and it lasts me 3 years instead of 4, but costs 250 instead of 600, I'd say it's worth it. I've also used an ex-corporate second hand laptop made in 2014 for 4 years from 2018 to 2022, and only after that did it start to die. It was a Thinkpad, which may have helped it's longevity. This is circumstantial evidence I understand, but in my opinion the lower cost and less environmental damage weighs better for me than maybe having to clean/replace the keyboard or battery. Buying second hand products originally known for their high quality construction or longevity probably helps too.

Whilst looking recently for second hand pixel 6 phones, I noticed a lot of them were hardly used, some even brand new and unopened, but still being sold at 200-280 gbp instead of new price 400+ for new.