Vacancy/Capex reserve: lump sum vs percentage of rental income?

[Ryan S.]

Hi BP, I'm looking around at new construction SFH rentals in my area, and it sounds like most lenders near me require 3-6 months of PITI in reserves before giving out mortgages.

I was wondering how this affects how much I should budget for reserves each month. If I already have enough saved up to cover major expenses and PITI for a few months to handle vacancy, do I really need to be setting aside 20-30% every month additionally for these expenses? Also worth noting that this property will be new construction, so I don't anticipate any major issues for a while.

FWIW, I have a solid W-2 and was not planning on withdrawing any of the post-reserves cash flow. All money will be reinvested for more properties, but I've been running these numbers to get an idea of how good of a deal this is.