There is no ideal number. My favorite advice is always this: Invest an amount that wouldn't hurt you financially even if you lost all of it. Although we all hope for the best and want to make profit, the crypto environment (especially the altcoin environment) is highly volatile and you never know what might happen tomorrow.
I agree. You should set a certain value for investment. You should now invest all of your money since it can make your living a difficult. Since the market is volatile, you can't say that it will go up and up. there will be a time that it will go down and when it go down so your investment is. So you should be careful when investing, and just be patient.