Old house - how much to budget for major repairs + maintenance?

[Palmira Angelova]

Hi everyone,

I'm considering investing in an older multi-family (~100 years old) around the Boston area. I only have experience with significantly newer properties and want to make sure I run the numbers correctly. Does anyone have experience with (very) old houses and how much to budget monthly/annual for
i) general maintenance
ii) major repairs (e.g. roof, plumbing etc.) 
?

I've found some related articles online but would love to hear about the experiences in the knowledgeable BP community. Thanks for your input!