Simple renovations, like changing a few walls or doors, can easily be handled by novices. In fact, they may be essential for upgrading an older home to modern tastes. Years ago, homes had separate rooms for the kitchen, laundry, pantry, informal dining, and family gathering room or den. Today, many of these are more likely to be one large space. If you are flipping an older home, you will probably need to tear out some walls to appeal to today’s homeowners. Older homes also tend to lack closets and a sufficient number of bathrooms. You will have to add those, as well. There is no point in telling a prospective purchaser that he or she can buy a beautiful armoire to use as a closet, he or she will just remember that your house has no closets. Bite the bullet and build some.
I generally discourage beginning flippers who want to replace windows. Removing old windows usually reveals rotten wood, poor carpentry that was covered up with layers of caulking, and irregular sizes requiring special orders. If you think the windows absolutely, positively must be replaced, then choose stock replacements that are kept in-store at most home improvement places.
Keep in mind the following story. A friend of mine special-ordered windows for his most recent flip project. The store told him they would be delivered in three weeks, which worked well with his schedule. Three weeks later he called to inquire about the exact date of delivery. The person at the store told him the windows were on back order, with an anticipated ship date two months later. His project is now at a complete standstill, waiting for those windows. Because of taxes, insurance, utilities, and interest, it costs him $5,000 for every month he stands idle. This is not an uncommon occurrence with special orders.