The life expectancy of a weed wacker is 3 years to 7 years, depending on how well it's maintained and how much use it sees.
Battery powered and electric weed wackers often last only a few years although some may last longer.
Gas powered weed wackers tend to last longer and Stihl weed wackers often last longer than other cheaper models.
When a weed eater only runs when choked it's often a sign of a clogged main jet in the carburetor which is a small hole in which the fuel is sucked up through into the carburetor into the intake to allow the engine to run.
If that main jet is clogged then it will either not run at all or run only on choke.
Other parts of the carburetor may also be the cause and so you would have to disassemble the carburetor and soak it in some parts cleaner such as Chemtool parts cleaner and then blow it out and rinse it off.
Or replace the carburetor on the weed eater.
A weed wacker that keeps stalling out can be a result of fuel or air delivery issues which can be a result of clogged carburetor, dirty air filter, fuel cap issues, or even bad fuel lines or clogged fuel filter inside the tank of the weed eater.
A clogged carburetor, which is often caused by old fuel or debris, can restrict the flow of fuel and cause the weed eater engine to lose power and bog down or stall at full throttle.
A clogged fuel filter and even a blocked fuel cap vent or clogged or cracked fuel lines can cause your weed eater to also lose power and bog down or even stall out.
When the air filter is dirty it restricts the airflow, which leads to a rich fuel mixture and bogging down or even stalling.
A clogged spark arrestor or even bad spark plug can also result in the weed eater bogging down at full throttle or to cut out when revved or at any other time as well.
Even bad gas or moisture in the gasoline can also cause your weed eater to bog down at full throttle or to cut out when revved or even cause it to start and die or not start at all.
Also an incorrect oil to fuel mixture or even straight gasoline can cause the engine of the weed eater to bog down or stall when revved.