I just started using good rain gear this year since I've been doing lots of LD riding in whatever the weather, year round.
Previously I just donned a wool baselayer and a winter jersey, got wet, and stayed warm. Then I started talking to the rest of my LD club and realized it's not just about staying warm... there's a comfort factor in there, and sopping wet wool (warm or not) is not comfortable to ride around in for a long time.

Now I have a Showers Pass Touring jacket, which is a bit on the heavy side but can take the abuse of being stuffed in a pack carelessly or balled up with spare clothes and used as a pillow for a roadside nap on a really long ride.
I can wear lighter weight gear underneath, and the zip vents, loose cuffs and cape vent in back make it fairly drafty so I don't overheat when it's 12 - 13C (55-ish F)
I hate having cold, soaking wet feet, so I use Gore Bike Wear non-insulated booties, and I'm considering going all out this winter with a waterproof helmet cover and some Showers Pass rain pants.

If it's warm out (closer to 60-ish F) then I don't bother with rain gear. Warm rain doesn't bother me.