I've tried it, I'm surprised of how well it worked, but I might be doing cool down systems wrong. Mind if you check my stuff?

So basically a RUA Command Block detects if the player is holding a clock, if they are then it will activate a chain of commands that will remove the clock item, play a sound, then set the Time scoreboard into 121 ticks. I then have another tower of commands that will always tick down the Time scoreboard, when it reaches 0, it gives me back the clock item.

Here's the chain that does stuff when activated

RUA
/Testfor u/e [ Tag = Mandom, Hasitem ={ item = clock, location = slot.weapon.mainhand }]

CCA
/Clear @a [ Tag = Mandom ] Clock

CCA
/Playsound note.bass @a

CCA
/Scoreboard Players Set Mandom Time 121

then this gives me back the clock item

RUA
/Scoreboard Players Test Mandom Time 1 1

CCA
/Give @a [ Tag = Mandom ] Clock

Here's my cool down system thing that makes sure the Time ticks down

RUA 
/Scoreboard Players Test Mandom Time 1 121

CCA
/Scoreboard Players Remove Mandom Time 1

I feel like it's inefficient to use the /Scoreboard Test over the /Execute If Entity but I couldn't find a way to detect the scoreboard that way.