You have to keep in mind that not all objects reflect the rays the same so depending what you're checking the reading can be off by some. Many have an adjustment but I never worried about it, I figured as long as I was within 10* it was fine. They've come in down in price BIG TIME over the past 40 years. The gun-type that were around $500 way back are now under $100 and I bought one a while back on sale for under $50. For a long time I used a smaller one I'd bought for around $30 to check tire temps. I was worried about the accuracy so much as consistency - I didn't care if it was off by 10* as long as it was always off by that amount.