Some players are die hard about insurance and blackjack. They insist on insurance remaining a part of their blackjack strategy.
It has been explained numerous times why insurance is bad for your blackjack odds.
For one thing it is a side bet. Side bets were created with the purpose of squeezing even more money out of players. The best you can do with insurance is break even. In other words you wager an additional $5 on a $10 wager just to hang on to your $10. It is still more money on the line, which is another opportunity for you to lose money. Losing money is bad for your blackjack odds and will lower them.
For another thing the only way to win an insurance bet is for the dealer to have that 10 for a hole card and to therefore have a natural blackjack. Hoping to win an insurance wager is hoping for the dealer to win the round. And there is something just wrong about hoping for the dealer to win.
Finally there are the blackjack odds of the dealer having a 10 card and the money involved in those odds.
A dealer only has a 31% chance of having a 10 card for a hole card. That is only four times out of thirteen: 10, Jack, Queen, King. The other nine out of thirteen, or 69%, of the time the hole card will be any other card.
Now we are going to say that you are wagering $10 per hand, which makes insurance $5 each time. In terms of money this means that you could expect to win $40: four times $5. So if there is a nine in thirteen odds that the card is anything other than a 10 card it means that you will lose $45.
So you see, by taking insurance you are hurting your own blackjack odds and losing more money that you would not have to. Insurance makes for bad blackjack strategy.