Why my laptop chargers never last?

What you are doing is moving around 

in a way that causes it to get spun up 

(e.g., always turning one way to put it 

down, then turning the same way when 

you pick it up). This causes the cord to 

get kinked up. Never pull hard on the 

cord in order to unkink it... unplug it at 

both ends (from the socket and from 

the laptop), pick it up and untangle/

unwind it, then plug it back in. Do this 

every few days (e.g., before going to 

bed or when you first grab it in the 

morning), OR learn to not always be 

spinning the same direction. Lastly, 

don't slam or kick the power converter 

brick around -- it might be a good idea 

to use an extension cord, or get a longer 

version of the charger cord, such that the 

brick always remains in one place on the 

floor (or wherever it normally lays). 

It might be you. All the laptops I bought, brand new and secondhand, are still in their first and original chargers. The one I bought brand new is already 8 years old.

Probably, because you are putting undue strain on them.  Cords rolled up improperly, allowing the charging port to take weight it shouldn't, allowing the plug in collection to be damaged in transit to and from.  I've had chargers for my laptops that have lasted 10 years!  AND they are still working.  When I'm done, I roll up the cable carefully, wind up the electrical wire carefully, always keeping care not to let any extra twists get in it.  I never use the charger while the laptop is on my lap, or on a bed, etc.  I use the charger to charge or power the laptop only when it is on a flat surface where nothing with interfere or come into contact with the charging port/plug.