If you are sexually active it is wise to get checked at least annually to be sure. A lot of std's will increase your volume of discharge.
If you aren't itchy and there isn't an odor than it most likely isn't an infection.
The above posts are right, it just depends on your body. I have discharge all month long and I freakin hate it, but what can you do? The amount and frequency changes from week to week and it has reduced a lot since I went on the pill.