What is the best age gap between babies

I had them close in age (3 under 3) and then our 4th 3 years later. There's pros and cons to both.

My two are 18 months apart and I am in love watching their bond grow and them grow with each other. It’s hard but so so rewarding. They sit there all day with each other just laughing and playing away 🥹

I had two under two … would not recommend

Ours are 2.5 years apart and it’s lovely. She understood what was happening, she was potty trained, helpful, wasn’t jealous. They are now 4 and 1.5 and they are the best of mates, she cried this evening cause he can’t sleep in her big girl bed with her.