Before I get into the question I'll mention that I fully understand the benefits of breastfeeding, and my wife and I do intend to attempt to breastfeed, hopefully as much as we can.
However, with the current global pandemic and increased difficulty making it to a grocery store or other purveyor of baby products without risking infection, I want to make sure that my wife and I cover our bases. Less access to our midwife may also be a problem.
What this means for us in terms of feeding is having formula as a solid backup after our boy's born. Currently we have about a month's worth of powdered formula, and plan to stock enough ready to feed formula for the first month - just in case he doesn't take to breastfeeding.
That aside we're also aware that formula supplementation is something we can do to make mom's life easier as she becomes increasingly exhausted from breastfeeding. I've heard comments like she should try to breastfeed exclusively for the first two months before we do any supplementation with formula, but it's surprisingly difficult to parse fact from fiction coming from Google.
My primary question is - what are the evidence-based best practices surrounding supplementing breastfeeding with formula? For example, is there a time period after birth where we should definitely avoid supplementing if we can, or is this rule looser than it seems? If we do supplement in the few months after birth, are there practical limits on how much or often we should supplement? Or are many of the sites found on Google somewhat alarmist, and we shouldn't be worrying this much?