Cap improvements vs. operating expenses

[Kenneth LaVoie]

A quick newbie question here!
After much great feedback from you and some hand holding from a couple of experienced, generous mentors in my town, I'm in the process of making offers. I have one expenses question though: I am using 50% of gross rents as my basic expense ratio -- even using a 10 year analyzer (excel) I have, when I painstakenly break everything down, it ends up coming close -- 42-48%, so I can trust that 50% number. My questio is, let's say the property doesn't necessarily need anything NOW, but the furnace and roof are 20 years old and I SUSPECT one or both will need replacing within 5-7 years. Would I use that number (let's say 5k new furnace) as a "capital improvement" and deduct from max offer price OR is that part of my 50% costs??

My current offers are on 2 single families. One is asking 94K,
and the other a pre foreclosure at 119k -- I've offered half price on each, using the standard equation with 100 desired monthly cf and 50% expenses and 5k cap improvments, but these cap imp. come from needing a roof MAYBE in 5-7 years, or same with furnace. They are actually in move in condition, so should I back that 5k out or leave it??
Thanks again all!
Ken