I've had vaginal discharge for as long as i can remember. it's heavy enough that i have to use a liner in my underwear. it ranges from creamy white to slimey clear/white. is this normal?

Yes: Asymptomatic vaginal discharge is normal. It is considered abnormal if it is causing itching, burning,or has an odor. Vaginal infections often are associated with a yellowish or greenish discharge sometimes tinged with blood.

See your doctor: Any abnormal or unexplained vaginal discharge should be medically evaluated. Even though there has been no change for a long time, this amount of vaginal fluid sounds excessive. If there is odor maybe bacteria vaginosis. It may just be your normal, but best to check it out, including STD tests if you're at risk (new partner, parter with other partners, etc). A gyn should be able to sort this out.

Possibly: Every women produces some amount of discharge and some more than others. Having a culture collected during a vaginal exam would let you know if this is a normal discharge as it should grow vaginal flora if normal. Things that might decrease your discharge include avoiding underwear at bedtime, shower over the tub, and good vaginal hygeine