Facts:Duplex in good structural condition (electrical, plumbing, foundation) but would need possibly $50k in cosmetics & updating if we were to rent out to average renter as opposed to steady stream of college students for the past 10 years.Unit 1: 3 BR, 1 BA.

Instead of just patching another 1ft section of plumbing i had GC come out and identify the cause of the problem/cause of loss and initiated an insurance claim. 

In the lease you want to make sure their are conditions (rules) to avoid arguments over backed up plumbing, burn out light bulbs, lawn maintenance, proper parking (not on the lawn) and use of common areas like a backyard if it is not partitioned off (ours was) .

I like plumbing rough in prior to electrical because if a plumber needs to reposition for some reason (like a drain hitting a floor joist) it is easier to have the electrician maneuver around that.

Crime rates, sewer inspections, electrical inspections, plumbing inspections, foundation inspections.  3. 

Roofs, kitchens, bathrooms, foundations, plumbing, electrical, windows, HVAC, hardscape are all expensive. 

New roof, new AC, moving electric panel (fortunately electrical had already been updated and house had been re-plumbed), new flooring throughout, new kitchen, new M bathroom, updating 2nd bath.

I bought a house and fully rehabbed it myself, learning everything from plumbing to electric and framing.

Well, since you can't rip the walls to look at framing, wiring, and plumbing, look at what you can see:1) Level of trim, appliances2) Finish carpentry or gaps in joints3) The flatness of floors and squareness of rooms. 

This will help you get a better idea of what tile, hardwood, carpet, plumbing fixtures and light fixtures costs for your rehabs.#3 Contact Local Contractors for Labor PricingCall local Subcontractors and get budget pricing for common repairs on your typical rehab project.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 a DatabaseOnce you start to get a better understanding of Labor and Material costs you will want to store this data in the spreadsheet.The House Flipping Spreadsheet has a database of common repairs & budget prices to help you get started, but you really need to start building your own cost database based upon your specific projects, materials & contractors in Chicago.#5 Practice, Practice, PracticeWalkthrough potential rehab properties (or find properties virtually online) and practice creating detailed scopes of work, quantifying repairs and estimating rehab costs for the projects.#6 Complete Your First Rehab Project It sounds like you are already half way through your first rehab?