Can you smell gas really bad in your house and you have been too lazy to buy a detector? Well instead of evacuating everyone out of the house and calling the fire brigade, why not just pull out that lighter from your pocket and light her up? That way you will know for sure if your house has a gas leak?
There’s a small chance your house may blow up with you in it if your lighter does test positive for gas though. But what can you do? You can’t win them all.