I decided to start looking for a safe exchange where I can buy and hold my Bitcoin for a very long term.
Mate don't get it twisted and end up losing all your money, time and energy on investing and accumulating bitcoin for a long time and end lose it all to an exchange due to your carelessness of believing that exchange are safe to use in storing your bitcoin in a long term. You are not the owner of your bitcoin when it's stored in an exchange because you don't have the private keys and your coins are prone to hack, exist scam by exchanges and your account can get frozen at anytime.
Bitcoin gives us the right to be our own bank due to her decentralized nature and by storing your bitcoin in a open source noncustodial wallet where only you have the private keys. It's better to store your bitcoin in a cold storage wallet either a hardware wallet or set up an electrum cold storage wallet where you generate the keys in an airgapped device. 70% of your total bitcoin investment can be stored in an offline wallet, 20% in a hot wallet and 10% in an exchange. It depends on how you want it.
Business and salary income can be used for other things like paying bills and as well as having emergency funds and reserved funds, then whatever is leftover could be the discretionary income meant for investing in bitcoin, it’s a simple logic.
No mate, you don't use your income or salary to set up your emergency funds reserve funds but your discretionary income. Because first of all, you should take care of your basic needs and monthly expenses before you can use whatever is left as your discretionary income to invest into bitcoin and build up your emergency funds and reserve funds as you have started your bitcoin investment buy sharing your discretionary income to two parts.
You use one part to buy bitcoin every week and the other part to build your emergency funds for at least three months of your monthly expenses simultaneously with your bitcoin investment