1,Time is money.
I think that we should not waste time because time is as important as money. We can't look at time and, can't have time eternally. Therefore we must value time.

2,A stitch in time saves nine.
If you have a small hole in a cloth, you can repair it with one stitch. But if you wait, the hole will get longer, and it will take you nine stitches. So this proverb tells us to take care of small problems before they become big problems.

3,There 's no time like the present.
I think that we should carry it out immediately when we decide to start something. It's the best day when we begin to start something. If we put off what we want to start something from now, we would lose our confidence.

4,Let's meet at four. If I'm not there by five, leave without me at six, and I'll be there at seven.
I have no idea about this saying. I think that a person who said this sentence is not punctual and is indecisive about time. So that means that we should be punctual for an appointment.