It turns out that we lose up to four days a year looking for where we have parked our car. http://news.sky.com/story/drivers-waste-four-days-a-year-looking-for-parking-spaces-new-research-shows-10751024

People often laugh at me but one way around this is to take a photo of where you have parked, make sure you include a street sign. In a car park I find this particularly useful as it helps remember the level and what row I’m in. I make sure I have the sign with the row information in it. Believe me this simple method has saved me a lot of time. 

If you have an iPhone 6 or newer and iOS 10 then if you have your iPhone connected via Bluetooth to your car’s audio system for calls or music it will remember where you parked your car in the Maps app, I spotted this when iOS 10 was first launched and was surprised when I opened Maps to see where I had parked and how long to get there. Here is how to make sure it is switched on if you want to use it. https://support.apple.com/en-gb/HT207227

Hopefully this will save you time and not spend up to four days a year looking for where you have parked your car.