Then you're not doing your tax returns properly.

You can claim depreciation on all your hardware (including your desk and chair).

You should be claiming some of your rent/mortgage as office expenses. And, obviously, your broadband cost, your electricity bill, your heating bill (if different), etc.

You can claim all the coffees you buy potential clients.

Having zero expenses is absolutely not what you want to efficiently run your business.

depends on the country. the value of doing all that work is simply not worth the money i would get back. so why bother?