I just transfer money from checking to roth when I feel comfortable. I'm not going to spend any more or less because I "hid" money from myself in my savings account, but I definitely know people that need to do this(my wife).
As much as I hate to admit it, I need to do this too.
Since I'm paid several times per week, in various amounts, I typically take about 80% to set aside for business expenses (retained earnings), taxes, retirement, investments, savings for large purchases. I live on about 20%, give or take, and I'm pretty comfortable.
People see the kind of car I drive and the clothes I typically wear and assume I don't make much. When I tell them what I earned last year, they have to be thinking I have a drug problem or something, because I just don't live like the typical young professional. Millionaire Next Door mentality.
Goal is to build a portfolio strong enough to support a high standard of living (large residence, boat, couple of classic cars, 4-6 weeks of international vacation travel every year, massive saltwater aquarium with pet sharks, hot wife, and couple of well educated kids) without touching the principal. And I want to accomplish this before age 50, I'm 30 now.