Projector shopping has one variable most TVs never need to worry about: ambient room lighting, which changes what actually matters more than resolution alone.
Brightness (lumens) matters more in a bright room
Lumens measure how much light a projector outputs — the key factor in whether an image looks washed out or vivid under real room lighting, not just in a dark theater. A projector with excellent resolution but low lumens can look genuinely disappointing in a room with any ambient light, while a brighter projector with more modest resolution can still look good in daylight. Matching brightness to the room's actual lighting conditions matters more than most buyers expect before assuming higher resolution is always the priority.
Resolution and lumens are solving different problems
Resolution determines image detail and sharpness; lumens determine how visible and vivid that image is under given lighting. A high-resolution, low-lumen projector in a bright room can show a technically detailed but washed-out, hard-to-see image — resolution alone doesn't compensate for insufficient brightness for the room.
Throw distance determines image size, and it's fixed by the room
"Throw distance" is how far the projector needs to sit from the screen to produce a given image size, and it varies significantly between models — a "short-throw" projector produces a large image from close range, useful in smaller rooms, while a standard-throw model needs more distance to achieve the same size image. Checking a specific projector's throw distance chart against the actual room's dimensions, before assuming any projector will produce the desired screen size in that space, avoids a mismatch that's hard to fix after buying.
A real screen usually outperforms a blank wall
A dedicated projector screen has a surface specifically designed to reflect light evenly and accurately; a plain wall, even a smooth white one, reflects light less consistently and can introduce a visible color cast depending on the paint. For anyone investing seriously in a projector setup, a proper screen makes a more noticeable difference to picture quality than many people expect before comparing the two directly.
The one thing people forget
Check the projector lamp or light source's realistic lifespan and replacement cost, not just the projector's upfront price. Some projectors use replaceable lamps that wear out and need periodic replacement at a real ongoing cost; others use longer-lasting LED or laser light sources with a much longer expected lifespan — a meaningful long-term cost difference that isn't obvious from the initial price tag alone.