To me with a ten year passport renewing it a few months early doesn't really matter. But I am always early doing anything. That's just me.

Pasport in Belgium is valid 5 years. Since a lot of countries ask fo it to be valid X months after visit, renewing it 6 months in advance means it would finally be valid 4 good years... But we get it in 2 weeks time.

Ps : I always write a wrong number when I book a flight - but always put a correct one for Esta or when asked by authorities.

I just don't understand what an airline should do with my passport number.

So I always fly under a wrong ID/passport nr...

But I'm paranoid, I just cancelled a hotel which asked to send a copy of my ID per mail... that was really too much for me.