AS a new rider and a Clyde, it matters to me. I purchased a Canari jacket that fit more like a typical windbreaker. I was not familiar with bike fit clothing at the time. Well, if I went over 15 mph, it would flap noisily in the wind and the drag was rediculous. AS the weather improved and I was just wearing a jersey, it was much more serene and I felt much less drag. Same situation when the wind blew and I was going slower. Now, everything I own as far as bike clothing is a little tighter. They do make relaxed or club fit jerseys which have the most room followed by semi form fit. These are what I aim for. Tight enough not to have tons of drag and noise yet loose enough to hide my gut (somewhat) and have mobility.

The Canari jacket went back to the store.

You don't have to wear it like a coat of paint but closer fitting clothing, for me, helps.

Frank