The younger you are - the more likely you will use certain carriers for cheap s/h. Also that you will use bus or other means to get to a port that is further away but with a cheaper fare. Parents and friends might take you there. Once you have children - the price goes up (say 2+2) but you are also going to look for a closer port. Aged 18 with a rucksack, taking a coach or crashing on a friends sofa for a night to get a flight at awkward time of day to save money? Easy. With awo adults and two children? with a drive, then a flight, then a drive, noise and air pressure? That changes your priorities.Then, when children have left home and you get older, you might be able to afford to use the big local port, rather than a cheaper distant one.
For the last 40 odd years I have had LTN to the north of me and LHR to the south. LGW is a minimum 90 mins by car and STN about 65. Over the years, I have compared prices of travelling to all of these and on the railiway to BRX and take what is the best I can afford at that time. Lastly, as I get older, we can afford PE and C for long haul. There is one route we have planned and it only goes from LGW early in the morning, so we'll drive down the previous evening with a stay + park at a hotel. If that route was served from LHR - we would use it.
My preference is always LHR as I live close to it and the higher cost of going there is offset by the convenience. I expect that most people go through similar stages of life and calculations depending on their circumstances. There are SO many factors to consider that just saying one airport is good and two airports better (or whatever combination you like) is too simplistic.