http://support.chess.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=31
From the above link:
STARTING VACATION
All new Chess.com accounts start out with 7 days of vacation time.
ACCRUAL
All members then accrue an additional 2 vacation days per month added on (1 on the 1st, 1 on the 15th).
What is the formula for calculating how much vacation time you get per day? does anyone know?