Assuming you have a limited and tight budget, how do you know what you must spend your money on right now and what you can delay to the future?

For example, would you delay spending money on legal stuff like drafting legal documents (e.g. privacy policies and terms of service), or a trademark? And do you think a lot of this varies depending on the kind of business? (We could argue some businesses take a greater risk by not having decent legal protection).

I often hear that when in doubt you should ask yourself "Does this help me get my first/next customer?". And I think it does make sense.

However, we often see some companies spend a lot of money on advertising (therefore following the 'Does this help me get the next customer' philosophy), but their success curve is like an upward spike that quickly falls back down after they stop advertising. I can think of many companies, especially in the crypto space (maybe the crypto space is different, though?) that did this and failed miserably.

The reason why is quite obvious. If you spend most of your money on advertising, your product will probably be quite shitty and while you're getting new customers, your retention rate will be small and your churn rate extremely high.

I understand it's about balance. But how do you find the right formula for your business? Is there an actual way to do this without spending a lot of money on testing the market and seeing what works and what doesn't? Maybe watching what your competitors did in the past to become successful?

Opinions?