One thing that is rarely thought of by many is how do you handle expenses that arise, or things that you want, that are greater than just a few paychecks? One of the hardest practices is to indebt yourself to an imaginary recurring bill that has not materialized. I take 10% of any monies I receive and place that money in my savings account. For the most part, that money get's used for auto maintenance costs, but it could be designated as a build up to pay for any large debt that paychecks cannot cover on their own. For example, saving up for a new car, home or for a vacation. Everyone should start a tithe savings, if you will, to put money away for something unforeseen, or, unattainable within your pay structure.
I think it is good to build an emergency slush fund, then have the discipline not to use it. I ,also think that it is worth it to keep building that way into investments once there is enough in there, or alongside it.