Yes it is a little frustrating when you have a surprise and cannot add anything additional for the benefit. If you max it out and don't use it all then your company gets to keep it. Yes it is a risk, but at the same time you can max it, use it all up and then quit without having to reimburse your employer (only for the medical portion, dependent care is available for reimbursement as it it contributed). Check with your HR. A few years ago changes were made to where 125 medical plans were allowed to roll over up to $500 to the next year. There were provisions to it though, one being your company had to amend the 125 plan allow the rollover.