They can be saved for a high point item. They points in the thread will never be reset. Just your points for the week. Say if you did 900 posts this week and 100 the next. They wouldn't add to get the bonus points for getting over 1000 bumps. Each week you get points from the bumps you did that week. Then they are added to you total, and then the next week's would be added. The only time your points go down is if you redeem some and then those are subtracted from your total.