How hard can it be?

Dates.

Times.

Just record them, and use them to answer simple questions, like “how long has it been since I started writing this post?”. How hard can it be?

People are good at fudging the details, and making it all work out. But machines are not, so software gets complicated very quickly. How complicated? A second entire blog post worth of complicated.

Be honest, how many of these assumptions would you have made before reading these?