[knaq]

Then you forget about the domain registration, or you are unable to pay due to hospitalization or finances, and you lose it.

Likewise for storage of data at home, there are floods and fires.

Reliably keeping your stuff long-term, both secure and accessible, is really really hard.

[toomuchtodo]

You can prepay up to 10 years into the future for most TLDs.

[ocdtrekkie]

As a note on this practice: Still renew it every year! It's easy to think ten years is a long time off to reach, but nine years of not doing anything and you'll have forgotten about it. And if you have lost access to something critical for renewal since then...

Renew every year, even if that date is far off.