In 2010, you came across a site that was giving away bitcoins. The site said it was free money so you signed up. You were logging in to figure out how it was money but couldn't. The last time you logged in you had more than 100 bitcoins. Later you forgot about the site until 2017 when a ponzi was advertising Bitcoin. Bitcoin? The name rang a bell and you stated hearing stories. You remembered you must have many bitcoins somewhere but you can't even remember the name of the site. How would you recover your BTC?
How can I forget such big amount of money, and I'm sure I have so many back-up of my wallet that time. Well, this is a situational example and it is given that we should protect our money to anyone despite of limited knowledge about of bitcoin. Mate, if you have big amount of bitcoin like that then you must use all the top setting to secured that wallet, and if you forget any of your private keys then it will be hard for you to recover it and the worst scenario is that, your bitcoin is totally gone now.