Occasionally, an idea pops into my head to do something—but I'm too busy to do it right away. So I tell myself I'll do it later, and move on. But recently I've noticed something funny: these things I say I'll do "later" almost never get done.
I think it's because we all live in the "now." Now is "now"; yesterday was "now"; tomorrow will surely be "now." And "now" is not "later": never do I sit down, say to myself "ah, now it's later, gotta to do all those things I put off!" and then do them.
I can follow through on specific things I plan for the future—like sitting down to write and edit this essay—if I say "I'll sit down at 4 PM to write." Why? Because 4 PM will eventually roll around, I'll notice that "it's 4 PM now," and I'll feel cued to follow through. And if I can't find a precise time to do something, it's pretty safe to assign it to a specific day, week, or month—because that broader target will eventually be "now," and I'll deal with it then.
But punting todos off to an undefined "later" is like kicking them into the abyss; if they ever get done, it'll be because they resurfaced somehow and got placed into a more specific queue. If I actually want to do something, but not now, I have to pin it to a precise future time.
The opposite is true too, and a fun trick: if I feel an urge to do something that wouldn't actually be a good idea, I can make myself a confident promise that I'll do it "later." "Of course I'll buy a new car. Just... not now. Later." And bingo—I can feel all the anticipation and dopamine and giddiness that comes from a big purchase, while saving myself some hassle and leaving my bank account intact. (I can also use my money multiple ways simultaneously in this manner: I can buy a Tesla and a new computer and some fancy books "later," and still have all the money left over!)
"Later" doesn't exist. Be wary of this, and abuse it where you can.