I never swatch. Ever. I’ve never made a swatch, and I never measure gauge (well, okay, occasionally after I’m half way through something just because I’m curious about it). I’ve knitted many things in my time, and I’ve never swatched for a thing. For most projects, I use the recommended needle size for either the yarn or the pattern. This is usually 8/5mm because I knit almost everything with worsted weight yarn.
Despite my lack of swatches, almost everything I’ve knit has come out about right. For example, I recently knit this hat:
It’s the Norwegian Star Earflap Hat (Rav link), which I knit to work on colorwork. The recommended needles are sevens, and I used an aran-weight yarn (Vanna’s Choice and also some random crappy acrylic from the stash) instead of a worsted. I cast on eighty because that’s what I always cast on for worsted/aran-weight hats. The hat fits perfectly.
Likewise, I didn’t swatch for my most recent sweater project, the cabled cardigan from the Fall 2006 Knit Simple (Ravelry link here). I’m using Vanna’s Choice, and I’m using 8’s because it’s what I have and it’s what I like to use. The recommended needles are 9’s. I knit both sleeves exactly as written (well, there are some pattern issues, so I made some educated changes, but I knit them exactly how they were supposed to be written), and I tried them on. They fit perfectly.
I imagine there’s a fair chance I’ll run into a problem eventually, but I figure a difference of a half a millimeter isn’t a HUGE deal. I’ll continue in my wanton, swatch-free lifestyle–until I catch KTD (knit transmitted disaster).