Number of days to hold search results?

[mjm]

Occasionally in a forum thread we will point to a 'search formatted' link at our gallery to find pics related to, for example wordA + wordB

During the search, the link changes to, example /search.php?searchid=750

Sure enough we have found that after the Admin selected number of days to hold the search, going to the link brings up the following:

Search id is not valid or has expired.

I have just found a way to overcome this, by changing the formatting of the link in the thread from:
/search.php?searchid=750 to /search.php?keyword=wordA+wordB

Hopefully this will make this link work permanently.

My question ...
I can't be sure, but I don't think our gallery search is used that extensively.
(We are now at searchid 750)
Could problems arise by extending - Number of days to hold search results
well beyond the default 10 days? (how does one set it as infinite?)
Could their be problems with performance issues?

Personally I can't see a reason why a user would want to retain their own search results, because once they have searched they are done.
So I'm guessing this feature has something to do with improving the way searches are done.
My immediate problem is to find all past postings at the forum that included a search link as /search.php?searchid=xxx to the gallery, which no longer work and change their format to /search.php?keyword=wordA+wordB.

[Chuck S]

If it is not used extensively you could raise the number but keeping the records limited ensures fast results