Matt-
What brand of valve do you have?
I've been using Champion manual valves & solenoid vavles for ~30+ years.
The brass valve bodies last a very long time, the electrically operated "valve actuators" can be replaced or rebuilt (your choice) & the solenoids can also be replaced seperately.
I've had to replace tacutators only once in 30 years (after about 20 to
25 years in service some still going).
I've got a couple actuators & rebuild kits sitting on my workbench, I might rebuild them if I get bored but at ~$30 for new ones every 20 years or so I've got some time.
Their website is down but was very useful when I visited when it was working
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I suggest using the brass units(either the compact one or the full sized ones) & statying away from the plastic ones.
Typically my solenoid actuated vavles fail closed & when they leak it's a dirt or rubber component problem
cheers Bob