Well, I'm not doing anything special to secure my btc. I keep mostly of my btc in offline wallet, which never been connected to online, desktop or mobile wallet. And offcourse, I'm trying to keep my private keys safely. I have saved it in several places to be guaranteed that if my device will crash, I wouldn't not loose all my btc.
Hodling btc in hardware wallet is a good idea. And on hardware wallet you can keep as many btc as you have or want to keep. Hardware, same like all other wallets doesn't have limit of btc allowed to keep.