Some people have questioned whether Randall Munroe can really claim that with authority, since he's too young to have any personal experience about what happens "decades" after you leave school. However, I'm now 40, and I still have anxiety dreams where I'm back at school doing my A levels. Each dream normally follows the same pattern: I'm aware that the final exams are getting closer, and I'm getting good results in Maths. However, I've been skiving off my Greek/Latin classes; nobody's come after me (e.g. giving me detention) and I don't want to turn up for the class again until I've caught up on the work I've missed, but I'm conscious that as more time goes past, the backlog keeps growing while I have less time to fit it all in before the actual exam.
In my case, I think it's partly because I still take exams. These are vocational rather than academic, e.g. Microsoft exams: I'm partly hoping that the qualification will help my career, but I also want to keep my skills up to date and learn new things. Up until now, there hasn't been much time pressure on these; I don't have to take them at all, so I can just wait until I'm ready. However, some qualifications now require you to re-certify at regular intervals (typically every 3 years). That means that even if I'm being diligent and studying something, I'm still conscious that there are other subjects which also need my attention.
Back in 2007, I passed the CompTIA A+ exam. In 2012, I enrolled in their CE program, which gave me 3 years to meet the requirements for the new A+ce qualification. I passed a Microsoft exam later in 2012, which gave me enough CEU points to qualify; I also passed the CWTS (Certified Wireless Technology Specialist) exam last month. However, I've also booked myself in for the Network+ exam this Friday; if I pass that, it will be the best way to convert/renew my A+ qualification, because I won't have to pay the annual fees. (All those links go to my tech blog, which talks about these exams in more detail.)
I've been meaning to get round to the Network+ exam for quite a while, so I've now got 3 different editions of the study guide, covering each new version of the exam objectives. Honestly, I'm a bit behind schedule on actually reading them, so I'm now moving into the last minute cramming stage. (Well, once I've finished procrastinating with blog posts, that is!) However, I did a practice exam last night and passed that, so I'm quietly confident: I have several years of relevant experience, so I'm not starting from scratch here.
Anyway, I'll close with a quote from a Red Dwarf novel ("Better than Life"), referring to Arnold Rimmer:
"He's got an exam in the morning. He's thirty years old and he's got an exam in the morning. All his life, he's always seemed to have an exam in the morning."