I think its depend on your site if your site is old then your site worth is more important for search engine.
Yes, it is quite a key factor in determining the value of a link to your site, and thus your PR (and as the two are usually relative, you rankings).
I think it plays a small role. For instance, if your competitor is a few years older than you BUT you have more quality links that they do (even if the link is younger than theirs), you will out rank them. ranking is always a combination of things
I suppose that it plays some role, but not so big. Also I think it's better to have old link, then a new one. I can be wrong.
I think google looks at is as if you link is still on a site for longer than a month then it must not be bought and it wasn't considered spam by the website owner.
An old link also means it's coming from an established site and source.. alot of sites disappear after a few years..
if your competitor is a few years older than you BUT you have more quality links that they do (even if the link is younger than theirs), you will out rank them. ranking is always a combination of things
I think google will minimize you if notice that links appear on some sites for month or so and then dissapeared. Esspecially if such link is in the sidebar or in footer.
It does have some weight in "Link Attribute" sector from SEO point of view. Just like if a page is indexed by Google for a long period of time, that page is important. On the other hand, if a link appear on a page for a longer time, the link is important. Even though if may not plays an important factor, but in SEO, every little thing counts.
it matters. even the speed of your site matters. It's just a question of how much? I think it has a minimal weight.
The age of backlink won't matter that much, however if lots of your backlinks are dropped after some time, it will make a negative impact on your rankings