Rental car acceptable damage varies by company and location. Often you are tired from traveling and the light is not ideal for identifying existing damage.
When you rent the car, take pictures of each section of the car and the wheels and tires. You will then have documentation with a time stamp as to the condition of the car when you rented it.
Do not delete the pictures for a few weeks (some car companies will come back to you even though the car was checked in with no damage noted).
Take pictures of your receipts as soon as you receive them. Then throw them in the garbage (as long as there is no confidential information on them). This is an easy way to keep track of your expenses and avoid lost receipts and “pocket litter”
Take a picture of the seat you like on a particular airline / airplane for future reference. There are sites that give advise but some of the reviews are outdated or skewed. It’s hard to remember which bulkheads have extra room, which are cramped, etc. Not a foolproof solution but better than guessing.
Take a packing square and put all the things you will want on your flight.(head phones, charging cord, Kindle, sleep mask, aspirin, reading glasses, etc.) Put the cube in the seat pocket leaving your feet clear. The cubes usually have a mesh or transparent side making it easy to find things in the cube. This keeps everything together and easy to find and helps prevent leaving items behind at the end of the flight