Fourth year FO commuter here and I can drop at least 3-4 days a month, usually more in overlap and giveaway. I can often drop 1-2 days in elitt as well. It takes a couple extra hours of work a month in bidding carefully and working elitt, but it’s doable.
In January and February I could have cleared my whole month easily due to the available flying right now vs bodies to do it.
In truth, it depends highly on the month, but we are able to easily move days around and drop days when needed. I haven’t felt “stuck” in a non holiday trip since I have been on reserve.