I've only made probably 5 connections so far. Have forgotten heatshrink before soldering several times, have soldered the yellow/green cable to the green cable instead of the yellow cable more than once and have forgotten to put the thread cap on a pigtail. I used to think I was systematic and thorough. Now I just think I'm going senile in old age. I have learnt to check everything, including connections before doing the heatshrink now though.