One of my job tasks was improving our custom string library. In VB! Sure InStr was slow: but we were trying to do "starts with" across very long strings. Sure,

One of my job tasks was improving our custom string library. In VB! Sure InStr was slow: but we were trying to do "starts with" across very long strings. Sure, it worked, but a slightly smarter solution was 100 times faster. Upon finding it I went on a search, I found it written nearly identical 10 years before me, in a different version of a string library (hint, that one was faster). The trick to knowing we needed to improve it: profiling!