I want to buy one domain which is old 12 years,but it was not indexed for years.I even conviced owner to redirect domain to my server,but then i was replacing server and completly forgot about this domain so it nonindexed again. So will i benefit anything with old age or i can forget about it since it is not indexed at the moment?
Old age domain is surely help to Pagerank of webasite.There is no need to confusion about indexing and indexing done to be faster.
If the price is reasonable, yes you should. There might be no PR, links, ect. but everything will be easier and faster if you do the SEO job well.