How do I plan for annual and irregular expenses?

List every expense that doesn't hit monthly – insurance premiums, property taxes, car registration, annual subscriptions, holidays, gifts, medical deductibles – add them up, and divide by 12. That monthly figure goes into sinking funds so each bill is fully funded when it lands, instead of blowing up an otherwise fine month. The reason 'good' months still feel tight is usually these lumpy costs that the monthly budget ignored. You can run one savings account with several named sub-balances, or separate accounts per goal. Once funded, irregular bills become non-events. Spend 30 minutes pulling a year of statements to find the lumps you forgot about, set up the automatic monthly transfers, and your budget will stop getting ambushed.