You really have to read the wikipedia page on ECC. There is the result of a large scale study by Google. Beside that, if you use a workstation with ECC memory

You really have to read the wikipedia page on ECC. There is the result of a large scale study by Google. Beside that, if you use a workstation with ECC memory and regularly utilized a good portion of that RAM (I use 128GB for bioinformatics / genomics applications), there is a good chance of witnessing an ECC error / MCE (Machine check exception). Here's the tl;dr "(i.e. about 5 single bit errors in 8 Gigabytes of RAM per hour using the top-end error rate), and more than 8% of DIMM memory modules affected by errors per year."