Unfortunately the batteries in my crystal ball have failed so, based on the information you gave, you will not get a lot of help here.
It's a Mac?
The OS is ???
The applications, that you leave running without quitting them, are?
I am having trouble with memory usage creeping up and up. Itg slowly goes up to 90% and i have to restart it to get it to release unused memory.
Slows the machine down somewhat.