Any insight or pros or cons on a rebuild kit ($30ish) versus a rebuilt box? ($250-300) beside price?

What is the life expectancy on these things if I go with the gasket kit on a steering box with 185K miles. Meaning, is it dumb to put new gaskets on a box with that many miles on it? Right now the steering seems fine...

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~shell
As of 2/2010:
2001 CLK55 0o\=*=/o0
13.6 @ 106mph
10K mi
1984 300SD
260K mi and going and going...
97 S600
46K miles
1991 Sentra SE-R (extremely dorked with)
www.se-r.net