I'm all for a routine of sorts.
DS2 is 10 wks, and I demand fed without any sort of structure until about a week ago. I've had no problems breast feeding and my supply is fine, but DS was often grizzly, sick a lot (posseting, not whole feeds) and really hard to settle. He was generally going about 2 hours between feeds in the day time and up to 4 at night if I was lucky. His weight gain is excellent so no worries there
After a couple of particulary crap days where he was crying for hours and seemed really uncomfortable, DH and I decided to try a different approach.
I felt that he could go 3 hours between feeds with a bit of encouragement. I thought this may help with the sickness, as he was feeding so frequently, he almost seemed to take too much then puke it all up, which was upsetting for him. So for the first day or two, when he seemed hungry after about 2 hours, I stuck him in the buggy or in the car to distract him. Magically, he always fell asleep, waking to feed after about a 3 hour gap.
I realized that I was misreading his cues. He likes to suckle himself to sleep, so when he got tired he makes feeding signs, like rooting, chewing hands etc. I assumed he was hungry, so offered him the boob. He would take a bit anyway, then doze off, then wake 10 mins later and throw up everywhere. He'd then be unsettled and whingy cos he was overtired.
Now, I feed him when he wakes, he takes a decent feed from both boobs - he was only feeding for 10 mins off one side before - and then he's awake for a bit. As soon as he starts to moan, usually 1-1/2 hours after waking, I swaddle him and give him a dummy, nad he's usually asleep in moments.
I cannot tell you what an improvement this is, and it's come about through trying a 'routine'. The swaddling has helped hugely - when he's overtired he thrashes about wildly and I thought he had tummy ache or wind, so I spend hours pacing and patting his back, when all he wanted was to be held still so he should go to sleep.
But having some structure to the day has been the biggest help, as I can predict more accurately what he wants.
Sorry for the essay - it's all very raw for me and it's cathartic to write it down! I'd say if she seems happy and content, then if it ain't broke, don't fix it and go with the flow. But if she's hard to settle, or miseralbe, it may be worth a try.