There are some problems with the division, and sure it could be possible that we could elect to have our basic expenses to be somewhere in the ballpark of 50% of our income, and once we figure out what our basic expenses, then the rest is discretionary income.
Portions of our discretionary income that we allocate towards debt servicing is not discretionary income, that is part of basic expenses.
With our discretionary income we can choose to invest (save), or consume. Each of us can figure out how much of our discretionary income we want to allocate to each of these.
Most people are not going to have 50% of their income as discretionary income, so 50% is pretty high. many will fit somewhere in the ballpark of 10% and 30%.
So what really matters is getting to actually know what your expenses might be, or surely will be before the right discretionary can be discovered and allotted. And secondly, in picking out our discretionary, we shouldn't be too desperate or greedy in a bid to increase our accumulation speed over night by allocating big percentage to the discretionary income which in turns increases your accumulation without properly settling your basic needs and much needed expenses, because if this is done in any was, would hunt you within the week or month of such rash decision.
One thing I've found to be very effective and advantageous in cashflow management is being able to project what your expenses would take out of your total income. If you cannot calculate your expenses before the funds come around, then you might not be able to utilize the funds properly. Being able to carve out a definite budget for your expenses would give you a clearer insight into what might be remaining as your discretionary income which you'll find easier to allocate it into accumulating Bitcoin and building out backup funds without any skepticism that you've used the money meant for your expenses for accumulating Bitcoin.
Another good point is that while projecting our expenses, we should have a clear classification of pending expenses into needs and wants. Every need should be considered but not all wants, some wants can be shifted to be handled by the next income to give you more leverage and not overburdening yourself to attending to many less important things at once thereby shooting your expenses budget so high unnecessarily.