There are lots of free resources that track supply and demand data like CBRE, MFN, Housing wire, Zillow etc.

If this is relevant for your market and operations: Assume that you will take home 1/3 of the commissions earned from a sale (which BTW is more like 2.7% per sale, NOT 6%, and really not 3% if you're taking the long view of the data). 

I know they have loads of data and there is a business reason they are doing that.

This data was collected from the US Census, which conducts a monthly building permit survey for every US metro. 

Bathroom hardward (TP and towel racks) - mount to a 1x4 plaque that is screwed to studs. you can pretty much hang on it without pulling out the hardware. i use entry level granite countertops - stain resistant, and should last a long time. i put LVP through the entire house, bathrooms and closets included. its water proof and scratch resistant. while the initial cost is more than carpet, you wont have to replace it as often. i use Sherwin-Williams Harmony line of paint, in a semi-gloss sheen. the semi-gloss is easier to wipe off for small marks, and the harmony line has deodorizers built in. for exterior door knobs, i use the smartkey knobs from kwikset. you can rekey a knob in a few minutes - no need to pay rekeying fees anymore. last tip - figure out which appliances your market typically provides. in my market, its not common to provide washers and dryers, so i dont. thats one less thing to have to repair. 4. i dont see an issue with the gas stove. to convert to electric you will need to have a 220V plug, which could be costly to install if not already there. 

There are a ton of data centers in loudoun county and prince William.

@Jacques Edouard Dessejour LapierreThe appraiser is going to have access to MLS sales and other data.  

Some data supports that my parent's generation (the baby boomers) are STAYING PUT as that generation is approaching retirement age.

I'm leaning more towards Northern VA due to the relatively friendlier landlord laws vs. those in DC, the job growth due to data centers, Amazon, and warehousing in that area, and the relative affordability. 

For one property I would check competition and adjust manually to have the absolute best pricing data.