WD-40 can temporarily silence a squeaky door hinge, but it is not recommended as a long-term solution. While it is effective at breaking down rust and grime, it contains very little lubricant and evaporates quickly. Using WD-40 can also attract dirt and dust to the hinges, which may cause more wear and tear over time. For a more lasting fix, after cleaning the hinge, apply a true lubricant. Better options include silicone spray, white lithium grease, metal or plastic lubricants, or oil-based products like petroleum jelly.

A slab door is a standalone door without a frame or hardware. A prehung door is a complete set that includes the door, frame, hinges, and sometimes the doorknob and lockset.

In most cases, a prehung door is the better and easier option to install, especially for DIY projects or exterior applications, as they often come pre-weatherproofed. They require fewer tools and less experience to install properly. Although prehung doors are heavier and have a higher upfront cost, the investment is often worthwhile for a complete upgrade that includes a new frame.

A slab door may be a better choice if you are on a tight budget, have a custom-sized wall opening, or only need to replace the door while keeping the existing frame. While the initial cost is lower, you will need to purchase all the hardware separately and do more DIY work to hang it, which may not result in significant time or money savings.

You can often fit a new door slab into an old frame as long as the frame’s in decent shape. The frame needs to be solid, square, and free of warping or rot. The new door has to match the old one in width, height, and thickness, and the hinge and knob placements need to line up or be adjusted carefully. However, if your frame is damaged, swapping just the door won’t cut it. In that case, replacing the entire unit would be the best move for a smooth, secure installation.

If you want to let in plenty of sunlight while keeping your home well insulated, your best bet is a patio-style door with two doors with full-view windows, including one primary door and one secondary door behind it, such as a screen door or storm door. This two-door system will let in plenty of natural light while maximizing insulation.