The only problem I've heard of with replacing a roof in the winter, is the temperatures being too cold for asphalt shingles to seal properly. 

But if you do it is good to have full gear, not flip flops and T shirt, to protect from the asphalt.

I mean pipe is pipe.. asphalt is asphalt etc etc.. some areas you may get that number down to 20 to 25k per lot but not a lot less. plus on top of that you have engineering permiting survey etc. 

You're probably a smaller yard, that runs about $30 a cut so you'll get off cheap, but in the winters you definitely don't want a drunk college student slipping on your pavement and cracking their skull.   

@Carloz Gil Charm does whole asphalt and metal roofs.

Pitched asphalt shingle?

I just had the inspection completed and there are a few sizable repairs needed: long asphalt driveway needs to be repaired, retaining wall rebuilt, some wood rot on the exterior, etc.

For example, call a roofer and ask what their average cost per Square of Architectural Asphalt Shingle Roofing would be on a 1,500 sf house, with a 6/12 pitch.Note: Some contractors will be reluctant to share pricing without seeing the property, but tell them you are just looking for a rough budget number you can use on future projects.#4 Compile Your Prices into a Spreadsheet or Estimating SoftwareOnce you start to get a better understanding of Labor and Material costs you will want to store this data into a spreadsheet or software that you can use to help you streamline the estimating process.The Book on Estimating Rehab Costs comes with a spreadsheet that you can use to help you populate your own database of labor pricing and material pricing.

Is this asphalt shingle or metal? 

@Charles Situ and slate tile under asphalt makes 0 sense what so ever, FYI.