PR I used the GF routine as a basis for what, approximately, the day should look like, but didnt follow to the letter. Good if you can take what you want and leave what you dont, IMVHO.
DD thrived on a GF routine. DS not there yet, am much more go with the flow with him, but there's no way he could wait 4 hours between feeds. He is a big hungry boy, can manage 3.5 hours at best, and that's only since I switched to the hungry milk and upped the offering to 8oz a time. Have been doing EASY routine ish, but last few days he has shown an inclinatin to have a big nap after midday bottle, and only a 5-10 min doze in the afternoon.
My own belief is that routine should be a balance between the baby's natural cycles and what you yourself prefer. I like structure, order, and cant cope with chaos! GF was all about what I needed. Now I have DS, I realise that it suited DD but doesnt work precisely the same way for DS. But some of the principles are good, e.g. offering them all the milk they need between 7-7, and maximum sleep during day etc. I also dont beat myself up if it doesnt work, just pull it all back for bedtime.