My adventures with my truck that decided to stop having problems one at a time and started ganging them up on me prompted me to start doing research, so I’ll share what I’ve got so far. I’ll put the tips about dealerships, financing, etc., in a separate message.
First, some of the car selection I need to do will have to be in person before I refine it online. The reason is that I am too big to fit into some of them without having to duck my head, and then when I get out, it feels like I’m having to climb up to get on my feet. With my pickup, I just move sideways and I’m sittiing on the bench seat. Plenty of headroom clearance at the door. There’s one model of car that I have an emotional attachment to because our family had one when I was a kid, but after riding in the 2017 model, I’d never buy it because it’s too uncomfortable to get in and out of.
I have a list of features like the above that are annoyances I’ve found in other vehicles so I can avoid them as much as possible. For example, side mirrors that are triangular-shaped might help with aerodynamics, but you lose as much as 20% surface area in the mirror itself, which means less visibility. Same goes with a body line where the doors slope upward and/or the roof slopes downward. Square windows, mirrors and body give you the most visibility for better defensive driving.
Check that the hazard lights are independent of the brake lights. Trust me, you may need this some day. As in having to stop quickly from 70 mph on an Interstate highway and you’re desperately trying to warn to the people behind you of the traffic jam ahead that they can’t see due to the curvature of the road and the hill it’s just beyond. On my truck, the brake lights are the hazard lights, so they stop flashing when you step on the brakes. I was told the car missed me by inches because he didn’t slow down as he changed lanes.
Look at the ground clearance under the front and rear bumpers. Are you going to be scraping curbs and parking stoppers when you go into a parking lot? What about entries to the lots that aren’t flat and even with the road? You might sacrifice some ground effects/aerodynamics and a little on the miles per gallon, but preventing undercarriage damage could be worth it. How many cars have you seen where someone spent a lot of money to get them lowered, and then you see them crawling over a speed bump to avoid scraping the car on the pavement?
Car alarms: some honk the horn when activated/deactivated, some just flash the lights. Is it selectable? Take this in consideration for your neighbors if you work graveyard or on-call shifts.
On some cars, they automatically unlock the doors if you put it in Park even if the engine is still running. Convenient, but what if you did that because you were going to be at a railroad crossing for a long time because a train is going by? Do you want someone who might be walking by to be able to open the doors? Auto-unlock after the key is turned off is better.
As Montgomery Scott said, “The more they overtake the plumbing, the easier it is to stop up the drain.” Do you need seats in a mini-van that can move sideways? Do you need “stick your foot under the sensor so it will open the door for you”? Do you need motorized side doors and hatch doors? Do you need heated seats? Do you need a built-in vacuum? For that last one, you can get a shop vac from Home Depot for as little as $30. What does the manufacturer charge for the convenience of a built-in vacuum, how much will it cost to fix it and how much of a hassle will it be to use it and clean out the filter?
Some key fobs have a panic button to activate the horn, but on one car, the end of the fob where the button is gets inserted into the dash so you can start the car. How would you use the panic function if you were in the car and it was running?
Cargo area in SUVs, min-vans, etc.: seats can fold down or be removed to increase cargo area, but for the latter, weigh having to have a place to store the seats. If increasing the storage area is something you need to do long-term, removable seats are stupid because you’re paying for something that won’t be in the vehicle very often. You’d still have that with fold-down seats, but at least converting them back into a seat only takes a few seconds instead of having to haul the seat out of your garage and reinstall it into the vehicle.
Folding power mirrors are good because they make the car narrower for tight areas. Check how close they sit to the door window. Will they accommodate a stick-on blind spot mirror?
On one or two rental vehicles, I couldn’t find a way to turn on the interior fan without having to start the engine. With more “no idle zone” signs going up, people might start getting snippy with you if you’re stuck with having to run the engine just to get a little air circulation.
Related note: you’ll often hear advice that running your air conditioner is better than rolling down the windows. Don’t forget that just running the fan will help your gas mileage a little more than using the air conditioner because the compressor motor doesn’t have to be activated if just the fans are running.
Oh, yeah, almost forgot. Don’t forget that with any advanced features that let you connect your smart phone, make getting those features wiped if you sell the vehicle later. The new owner might be able to see that old data. Likewise, you could snoop on the new owner’s activities if the connected features are still registered to you. See the “Buying a connected car or house? Better get it wiped” thread for more details.