Need help understanding setting up cofounder vesting: what's standard?

I publish illustrative scenarios prepared by my practice. All participants and conversations are fictional. The fictional posts are not posts by real users, accounts of client experiences, or reports of actual results.
Illustrative scenario prepared by my practice.
For informational purposes only. Not legal advice.
Hypothetical question

My cofounder and I are splitting equity 50/50. Someone told us we need "vesting" to protect ourselves. What does that mean and what's typical?

Illustrative response

Important: vesting is about EARNING your equity over time, not about giving it away. If you both commit for 4 years, you both end up with your full 50%.

The cliff exists because someone who leaves at month 3 shouldn't own half your company forever.

Illustrative response

PLEASE do this. My first startup: no vesting. Cofounder left after 8 months with 50% of the company. I built it alone for 2 years and he still owned half. Had to buy him out to raise money. Nightmare.

Illustrative response

Should we both start vesting now (at least in my experience), or should we give ourselves credit for the 6 months we've already been working on this?

Illustrative response

We decided: 4-year vesting, 1-year cliff, 6 months credit for time served. Both filed 83(b) elections. Thanks for the help!