Self-managing gives you more freedom over how your funding is spent, and the most common worry that comes with it is spending it the wrong way.
The test is simpler than it looks, though it's worth checking specifics against current NDIS guidance, because arrangements change.
A support usually needs to relate to your disability, be connected to the goals in your plan, represent value for money, and be something the scheme funds rather than something considered an everyday living cost.
Most questions people have answer themselves against that test. The ones that don't are worth asking about rather than guessing.
Everyday costs. Groceries, rent and utilities are generally living expenses rather than supports, even where disability makes them harder.
Things for other people. Support is funded for you, not for a family member, even when the family member is doing the caring.
Rates above the limits. Price limits apply to many supports. Agreeing a rate above the limit doesn't make it claimable, and the shortfall usually lands on you.
Paperwork that doesn't exist. Even a correct payment needs an invoice and a record. This is the most common problem, and the most avoidable.
An agreement with each worker covering what they do, when, the rate, cancellation terms and how either of you ends it. An invoice for every payment. A record of what you paid and when.
Keep them somewhere you could find them in five minutes if you were asked, because occasionally you will be.
Ask before you spend rather than after. Your support coordinator, your plan manager if you have one, or the NDIA directly. Nobody minds the question, and everybody minds the unwinding.
Make sure you have a written agreement with every worker you use. It's the one thing most struggling self-managers are missing.
Find Your Support Team. Agreements and invoices are created in Support Network, not kept in your head.