For the home hobbyist, the HF calipers work just fine, they come in 4" and 6" sizes. I use the four inch the most, and when I need a long length, I pull out a 12" or the 18" that stays in a case in the shop, the little 4" are all over my shop, several on each work bench or machine. The electronic ones all use the same chip, and I have checked them over the years for accuracy, with a known sized test block and never noticed any issues. Keep them clean, keep a bunch of the batteries handy, bring them inside in the winter, the battery lasts longer that way. I always have several blister packs of spare LR44 batteries on hand. I buy them at Walmart's electronics department in four or six packs. Same with my Igaging DRO setup on the mill, they also use the same chip as the Calipers.