Remember this everyone, you can only bid what you accrue in a year. Keep this in mind if you are younger then 50 and go on the ridiculous quest to get to "use or lose status". It's always good idea to carry over 2-3 weeks of leave a year if you can, and you do want to retire at the brink of use or lose status to get that payout, but you might be falling into a trap if you get there too soon.
Once again you only can bid what you accrue, so if you carry over 6 weeks from the previous year at use or lose numbers, you better be able to get spot leave for 6 weeks a year because you can't reserve that in the bidding process. With the FAA in bad shape with staffing in most places (at least how they phrase it), it can be ultra hard to use 6 weeks of spot leave. And often times when you can, you are not going to get 6 extra full weeks off or anything close to that, unless you truly are at a overstaffed facility where spot leave is always approved. You will be taking off individual days here and there, often in the middle of your work week, as that is the only time you might be able to get the leave approved. That is not a good enough reward for me for taking very low levels of leave for years to get to the coveted use or lose status just to say you did it.