Gauge swatch questions

Hi.I was wondering if a person has to block (wet)their swatch?would it make any different in the sets and rows of the swatch?I know that when I was taught knitting a gauge swatch they never said anything about wetting (blocking) a gauge swatch?.wouldn’t the swatch while wet making the sts expand and then dry go back to original size? What are you guys opinions on it?what do you guys think.

Yes, no, maybe.

Yes it will change. No you probably don’t have to, the swatch will be close enough. Some fibers may change enough that you have to if it’s something for a very perfect fit.