If you're pro-choice all the time, then you think people should get abortions for any reason. If a stupid drunk slut gets knocked up at a party, you don't believe she should have to face up to what she's done, but rather terminate the foetus for her own convenience. You also believe that people who have unwanted pregnancies after having unprotected sex should be able to terminate the foetus, despite it being entirely their fault. In short, you believe that its more important for irresponsible idiots to not have to face consequences than for the foetus to become a baby with its whole life ahead of it.
If you're pro-choice sometimes, you believe that in instances where the woman has been -blam!-, or giving birth will affect her wellbeing, she should be allowed an abortion. You also believe that if two people DID take precautionary steps to having sex, e.g they used two or more forms of contraception with a high success rate, and by the very small chance she gets pregnant, it was the contraception that failed and she should be allowed an abortion. Not just any irresponsible idiot should be able to terminte a foetus because they screwed up.
If you are pro-life all the time, you believe that no one should ever be allowed an abortion. If her health or even life is at risk, she should sacrifice herself for the baby. If she was -blam!-, you believe that she has to give birth to her rapists baby.
So which one are you?