I get what your are saying but in my experience it is probably better to leave it well alone and build links to your buysomepants page, rather than changing the url.

It still contains your target keywords, but i would argue that if is receiving a decent amount of traffic and has done for a while, leave it alone.

If it is receiving zero traffic then sure go ahead and change it, but make sure you put a redirect in for those that have already bookmarked/linked to that page.

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Search engine optimization from a different angle