Not sure from your phrasing if you are wanting to work, or wondering how much you will HAVE to work... If you WANT to work, you can work 16-17 Days a month. Or even more up to FAR limits or Average Line Value +15 hours. ALV is between 72-84 hours for NB. It is generally lower in the Non-holiday winter months, and highest in the summer and holiday months. Generally.

If you DON'T want to work, it really depends. There will be months where if you don't do anything 'to your advantage' where you might get slammed at 16-17 days of work - basically every day you are on reserve, or nearly so. I would say that's not terribly common these days, but still possible. The good thing is we will continue to hire at least 100/month UFN (more in the next couple of months). So you will have a steady supply of NH's behind you to raise your seniority, and soak up the worst of it. Once you get more senior, and with just a little knowlege/planning, you can easily average 10-11 days of work a month on an annualized basis, or even less in some categories/seasons. It does vary with the flying seasons, where April (Spring Break), Summer and Holiday months being more. But again, it depends on the category. You will hear various answers from different folks' experience.

I'm a middle-third Captain who was super senior FO when I upgraded. But I've also been THE plug as WB FO. I have always bid reserve by choice (even as a commuter) because I almost always work less and get paid at least as much if not more than I would with a line.