When should you introduce tummy time?

I started day 1

I have a 3 week old and his Dr. told me yesterday that I need to start it daily. She said that they have the muscle strength when they're born but if you don't do tummy time regularly they loose that strength which could delay their milestones.

Do your babies like it? Mine (5 weeks today) screams and cries so she ends up doing less than a minute

My pediatrician said to start right away but be careful until the umbilical cord falls off.

My pediatrician said once the umbilical cord falls off.

I started after his umbilical cord fell off and his circumcision had healed. Ped said 5 minutes a day but I do more depending on the mood of my son. 2 minutes here, 3 minutes there, every little bit counts.

My pediatrician has us doing it starting at 2 weeks. 

My 4 week old has done it straight away as shes so hard to burp i have to lay her on her belly to help bring uo the wind. Shes so strong already supporting her head and turning it

When their umbilical cord falls off I start 3-5 mins a day