No, not Parkinson’s disease, Parkinson’s law.  It’s one of the most important aspects of work and time management.  The law is this:

Work expands to fill the time available for its completion.

That means that if you have a task and give yourself the “next five hours” to get it done, guess how long it will take to get done?

Five hours.

If you have the same task, and instead set a timer for two hours and force yourself to get it all down before the timer goes off, guess how long it will take to get done?

Two hours.

Same task, completely different completion time.  Parkinson’s law also applies to long-term projects.  If you give yourself two months to complete a big project, that project is guaranteed to take you two months to finish, or longer.  If instead you gave yourself three weeks to finish the exact same project, guess what?

One of the biggest mistakes people make is to look at their to-do lists in the morning and say “Okay.  I have the next eight hours to get this stuff done.”  Bad.  Not only will you likely not get it all done, your work will expand to fill those eight hours.

Much better to identify the key items in that list and then force yourself to get it done within one or two hours.  When you finish, take a quick break, select some new items, then go on burst mode again for another one or two hours.

I am constantly aware of Parkinson’s evil law and I always make sure it doesn’t artificially expand my work times.  You should be too.