Hi guys, newbie here.

I'm wondering how does something like the tiagra groupset compare to, say, 105 and dura-ace?

Now I know that it's not really a fair comparison but I still want to know.
I know that dura-ace is made to be light, while something like tiagra is made out of heavier, stronger (more robust) materials, but how does that matter in the long term? I'm talking like 7-10 years down the line, if the parts are being cleaned and serviced equally good?

Thanks!