In our schedules, we invariably encounter disruptions that causes some timelines to slip. If all 24 hours of our day is fully packed with things to do, then such a slippage will cascade down the list of tasks, causing a slippage in everything else that comes after.

You would have noticed this when you over-run a meeting by 10 minutes and have three other meetings that follow it back-to-back, causing you to over-run each of those by 10 minutes as well. 

Slack in your schedule will help absorb such slippages. 

More importantly, slack to absorb such slippages gives you a peace of mind and doesn't make you feel like you're in a rush all the time. 

When you don't feel like you're in a rush all the time, you have the time to care and think beyond what's immediately needed to tide you over. 

Someone only manages to think about investing for the future when there is money left over after covering all the monthly expenses. 

How much slack do you have in your schedule?