Sick of chipping in for birthdays and baby showers?

Not only is there no such thing as a free lunch, but those birthday cakes for co-workers can cost you, too.

It's not unusual to be asked to help pay for celebrations at the office, such as birthdays and baby showers. That's according to a recent survey by OfficeTeam, in which more than 75% of those who responded said employees chip in at least once a year; 15% said employees receive donation requests monthly.

Avoid asking colleagues for too much too often by keeping in mind these guidelines from OfficeTeam:

• Keep it selective. Asking a new hire who has never met the mom-to-be to contribute to a baby shower is unfair. Instead, extend the invite to those who are most familiar with the person receiving special attention.
• Keep it reasonable. Rather than specifying a dollar amount, ask co-workers for voluntary contributions of any size toward buying a cake, gift or other item.
• Keep it low-key. Sending a general e-mail announcement or circulating a donation envelope for anonymous contributions is preferable to a personal plea, which can make people feel uncomfortable.