Putting things into buckets
That’s all budgeting really is.
The trick, I think, it making sure you put your money in the right buckets to start, before you allocate money for less important buckets.
Your rent and 401k are first-tier buckets.
Groceries and wifi are second.
Travel and entertainment are third.
If you can put the right amount of money in the right buckets—by planning ahead—you can ensure that what’s “safe to spend” cascades down.
Which makes knowing whether you’ll have enough to spend much easier.