I never lost any single Bitcoin nor altcoins. I quite few times heard and read that some people were complaining or remaining without funds from wallets. There should be taken some extra steps when you are willing to store your coins locally. A good antivirus with encrypted wallet is good way of protecting like me.
it is very good that nothing bad happened with your bitcoin but what if automatically btc became loss in your wallet . And what happened when during the transaction you find that there is double deduction in your wallet for single transaction . this is totally luck that you are free from any type of btc lost .
I have never faced any issue of double deduction or bitcoins getting lost from my wallet automatically, as all the wallets are very safe with security measure so its not easy for anyone to steal your coins.
Most of the wallets are very safe. I mean the off line wallets. I use the Core wallets without problem.