If you have done some simple carpentry type work before, have basic tools, and the building was constructed within the last 40-50 years, then you're probably good to go yourself after watching a few YouTube videos.You could start with pulling off the trim and looking at how the current door is installed (assuming you mean the full door and not just the slab).

The new door slab width might not match the jam requiring you to trim the width.

Semi gloss white on trim.

I dealt with this in a condo I bought from a smoker.1) Open windows2) Definitely rip up any carpet that may be there3) Put on a mask-  Clean and scrub walls/windows/floors/trim every surface in the house with bleach/water mixture.

Aloha,Before you request new proposals from a variety of vendors, you need to determine what, exactly, are your requirements.You should have an accurate total yard size, not "probably about"; how many linear feet of concrete edging; are there shrubs, hedges, or trees to maintain and/or trim around, and estimated sizes; other obstacles to work around or be cautious of; is loose trash, or excessive fruit dropping, an issue that needs to be addressed prior to mowing; minimum/maximum grass height expectations (address areas where scalping might be a problem, and how "rain days" are handled in terms of scheduling and charges); what type of schedule do you actually need; are you ok/is property suitable for using string trimmers for all areas, or must they use a push/ standard mower; bag and remove the waste, or blow it to specific area (that will not upset your neighbor); do you require periodic weed killer/fertilizer, and spot weed killer; is there/do you need an irrigation system to properly maintain some/all of the yard area (if so, the system should be checked periodically for proper operation and settings, and at every visit after mowing/trimming complete all heads should be checked to ensure none are broken); and most importantly, be sure your vendor has appropriate insurance to protect YOU in case of injury to your tenants, their vehicles, your property, or the workers, caused by their operation of rotating equipment or other job related efforts.

ARV:  My estimations are about $650,000 - 700,000 for a tri-plex and a quad-plex would be about $700,000 & upBiggest costs I can see are the obvious purchase price, demolition costs with all the dumpsters, foundation fixing or new foundation depending on the age and condition, Framing, siding/ext. trim, plumbing.I'm trying to see if this is worth going this route. 

FIgure out any other materials (doors, finish trim, flooring, siding, roof tiles, etcc etc.)A good rough number for just a home build is about $150 per square foot, but remember this is a quadplex so you need 4 kitchens, 4 bathrooms, etc etc.

Did one repair job for $250  when someone else tried to charge like $1000.I know a painter and trim installer who works on a $200/day flat rate. 

But when we decided to sell last January, we decided to give it some cosmetic TLC, and with trim work, flooring, paint, and some landscaping, it sold for about 30% more than the next most expensive house in the neighborhood.

Or what if ceiling trim paint starts to peal?