Unless you open the cooling system you should not have to bleed the system.

Just adding a top off should not require it. However, anytime I open the expansion tank I open the screw thats up on the tank just to be safe.

The other answer to your question is no. Your loosing coolant somewhere so start looking for a leak. If its just a drop or two out of a hose or a water pump its drying from the heat of the engine before it can puddle up anywhere.

You have a leak somewhere .. you just have to find it.