If you are at a junior base with PSA (DAY/CVG/DCA), you should be about to hold a line within 2-3 months of completing training. Then, you can use the SAP to take any time off that you want. Once you hold a line, you can take every weekend off.
With the senior bases, it will take 6-8 months from new hire.
Schedule Adjustment Period (SAP) will let you take any days off that you want. No questions asked.
You can be with the company 3 months out of training in a junior base, have every weekend and holiday off, and work as few as 12 days a month or as much as 19 days a month, depending on how much you want to fly.
If it takes you 2 years to get every weekend and holiday off, then you are doing it very, very wrong.