Memento Mori

In ancient Rome, when a general returned from a successful campaign, a victory parade on his honour was organised.
It must have happened that Generals would grow too cocky after one too many parades, the adulation and glorification, and then they would get sloppy and lose. Romans introduced a little trick to try to avoid that terrible fate for the general but also the roman troops, morale and coffers.
Accompanying the General in the parade there would be a servant, who would approach the general when he seemed drunk with power and whisper in his ear: "Respice post te! Hominem te esse memento! Memento mori!" or "Look behind you! Remember that you are but a man! Remember that you will die!".
For us non glorified generals there is a lot of value on this reminder too. Our time is limited, and a reminder of such limitation might help us live more present, more fully.
I recently found the "Memento Mori" calendar. It's a simple device: every week of your life is a square that you cross, or fill, once it has passed. It's not coming back, and every time there are less squares left.

To me, it reminds me to be present and to take action. What am I waiting for? My parents will die sooner than me (if I'm lucky) and my time with them is limited. My friends' and loved ones' clocks are also ticking, and they have their own things to deal with. Every minute with them is a gift, so why waste it not being present?
Oh, and I have been not present. I have missed what was right under my nose. It cost me dearly. No more.