In most cases it's more important that your stitch gauge be correct than that your row gauge is.
Many patterns will need you to cast on a certain number of stitches then knit for X inches. Like a sweater front and back, sleeves, sock, etc. If this is the case the row gauge really doesn't matter. Just make sure you know how many rows it takes to get to X, so your other sleeve, sock, ... will be the same length. If there's any shaping involved, ie. waist shpaing on sweaters, increases on sleeves you may need to adjust where the increase is. If your sweater pattern says you should have 8 rows to the inch and you're supposed to increase every 12 rows (1.5 inches) and you're getting 10 rows per inch, then you'd need to increase every 15 rows or so.
Knitty.com had a good article on this several months ago. I think it was called "thinking beyond the pattern".
If you have specific questions on adapting a pattern, just ask. I've done this a lot. I've got one VERY tall DS, and two short, petite, but busty DD's so I need to adapt something on almost everything I knit.
Happy Knitting :XX: :XX: