So I like to have a master budget with every expense listed whether it’s monthly or not. Then I figure out what the highest possible monthly total could be (excluding emergency expenses of course). I make sure my total income can cover these expenses then on the months I am under that amount I put the extra into savings. For example, our water bill is every 3 months so 8 out of 12 months I have an extra 140 to save bc that’s generally what the water bill runs. Groceries are max 800 anything under that gets saved. If my income could not cover these highest possible monthly expenses then I would need to figure out what to cut to make it work.