There is a myriad of reasons why people find it difficult to develop a monthly spending and savings plan. Having a variable income can make it difficult to plan ahead for what can be saved each month. Unexpected expenditures are just that, unexpected. We work and save so that we can afford things like trips, nice dinners, home improvements, or however you want to enjoy your life. Reward yourself for your accomplishments instead of feeling regretful about not saving.
Checking and Spending Account(s)
It should start with a budget. I am not talking about analyzing the fiscal deficit here, but you should work to understand just how much money you spend per month on repeatable things. Include what you spend to live and enjoy your life. For example, my wife and I enjoy entertaining, so we include that in our monthly budget. Start with your credit or debit card statements and work from there.
This account should hold enough to cover your expenses for the next month but shouldn't hold much beyond that. This is called zero-sum budgeting. When you find this account with more than you need, then allow the excess to waterfall to your next account - your savings account.
Savings Account
Use this account to hold cash that you can draw on when needed or wanted. You can define this amount based on the bigger, lumpy expenditures you can reasonably expect in the near future. If something major breaks at my house, I turn to this account. If a quick trip gets planned last minute, I turn to this account. I've heard people recommend holding 6 months’ salary, but I think this is way too much. You should set this amount based on your spending expectations and goals.
You can earn return on this account if you play your cards right. Most banks offer checking and savings accounts as one package but pay attention to how much interest they are paying. There are plenty of other options to increase your interest easily, just do some research like they provide here: https://www.nerdwallet.com/blog/banking/best-high-yield-online-savings-accounts/.
When you inevitably draw money from this account, it should be a priority to refill this bucket. However, if you find that your balance exceeds your needs for this account, allow the excess to waterfall to your next account - your investment account.
Investment Account
A first priority would be to maximize the contributions to your 401(k). Remember that if you increase your contribution by $1,000, it is with pre-tax dollars. The impact on your paycheck would not be equal to that $1,000, it would be $1,000 * (1 - your income tax rate).
If you are already maximizing contributions to your 401(k), you can open an investment account. These accounts should be invested in securities that align with your portfolio. However, it is important that you should do your absolute best to maximize your contributions while avoiding any withdrawals.
Pulling money from this account would require liquidating investments which brings in the costs and risks of being a short-term investor. Taking withdrawals from an IRA could also subject you to unnecessary penalties. These investment accounts should be held, and protected, for the long-term.
This account represents the trade-off between saving for the future or spending now. Once you start to see a consistency in how much you can invest per month, make that your standard and do your best to repeat it, if not increase it.
This may not be teaching you anything new, but maybe just reading this could be your first step to taking action. Keep yourself in check and have a plan.
Checking and Spending Account: Set your zero-sum budget - what you spend each month.
Savings Account: Set your savings budget - what you want to hold in cash for medium-term, lumpy expenditures. Shop for a good rate.
Investment Account: Insulate this account and reward yourself for increasing this balance.