I use the almost-soppy towel method about half the time!
It REALLY IMPROVES the look of your knitting. The stitches even out!
I knit a little baby girl set a couple of years ago, using a single-ply polished cotton. Single ply yarns get all wonky over the st stitch. It drives me crazy crazy! I blocked this little outfit using the wet towel thing, but I didn't have high hopes that it would remedy the wonky st st! GUESS WHAT? It did! I couldn't believe it! So happy!
Blocking is used before seaming for a variety of reasons, one of which is to IMPROVE the surface quality of the pieces! Some folks will not block because they already like the surface quality...but IF THEY WOULD BLOCK regardless, they'd like the results even better! Blocking always improves the knitting! Always.
Blocking made this little girl's cotton sweater almost look machine knitted!
You should have seen the wonky stitches before blocking!
Here's another little girl's cotton jumper! (after blocking!)
A lot of folks would not block cottons or acrylics. I do.
The only thing I do not block are blankets!
(Like this log cabin blanket shown below!) (it really is a blanket, not a rug!)
But I will block afghan's that are knit in squares.
I block the squares before seaming them all together.