Let me give an example - i have a link on a good website,high PR .now,if i would have to choose between paying again for this link to keep it there,or to buy a new link on a new website (of the same value) (and than mean removing the link on the website i have it now).what is better for google? puting my link to the new website,or continue with this one ? thanks
I would stay on the old site if it has a higher PR and is relevent to your topic. But which would bring you the most traffic (if any)? Sometimes there are reasons other than PR link juice to place a link.
I would stay with the old one, Google likes it when a link is there for a while, but if the content on the new site has better content and is more relevant to the the link then it might be worth changing.
the old link is not on a relevant website,but it is a respected one .i will see if i will find anything better,but i don't think so.i can't find relevant links with high PR and for this link,i am interested in PR juice,not on traffic
you have to know that the older your link is the most value you will get from it, one of the easiest ways for google to filter paid links is to Null them for a period of time before crediting them (they hope that the link buyer will not notice any benefits from that link and drop it)
Old on should be better, because it has maintained its PR for long and most likely will maintain in future. Of course you should consider other points like relevancy, traffic, quality of the site the link is coming from etc. etc.
Leave it on the old one. As far as I know there is only advantages to age for links and domains. There could be downsides you don't know about for the new link.