Using YNAB’s sinking funds helped me get out of my considerable divorce debt. They’re like envelopes you put money into ahead of time, for every single category/thing you want to spend on or save for.
If you need to spend more than is in the envelope, you must transfer from another envelope first
If a bill is higher than expected, transfer money from another envelope
If you want to make an impulse purchase that doesn’t fit an envelope, make mine and transfer money in from an existing one
And so on. It’s a great system, and I continue to use it even though I’m now debt free, except for my monthly bills and car lease payment.