Repair Permissions...

In the year and a half since I bought my Mac, I have only done "Repair Permissions" twice. I think it was last winter the first time and then last night was the second. In both cases it was after the Applications folder wouldn't let me put something in it that I wanted on the system for all users. I was told the folder was locked. Well, the Disk Utility repaired permissions nicely. I really must get up the energy to research why this happens. I know I had a few programs in trial mode in and out of the Mac, and in fact just two nights ago I was trying out Mariner Write and I put that program in the Applications folder. So perhaps the tossing of that trial demo and the associated files was my problem. Who knows. I do know that the advice offered every time an update from Apple comes is to do Repair Permissions before and after the installation. So, perhaps once in awhile I should do this routinely.