Tubes wear out because the vacuum degrades and the filaments burn up at higher oxygen levels in the tubes. Since you cannot keep a good vacuum forever, this is inevitable.
Solid state devices can fail as well, but this is more determined by the original design and support circuitry than the devices themselves. I have Tektronix measurement gear (such as amplifiers and O scopes) that were built in the late 60's and early 70's using the earliest solid state transistors that still meet factory performance specs to this day. That is because the power supplies and bypassing components were of military or high commercial specification, and voltage transients from the power line did not get in and destroy those transistors.
While you can perhaps overload a tube circuit without a big issue, overloading a solid state circuit can spell disaster for a semiconductor. Under certain conditions, overload and secondary breakdown in a transistor is measured in microseconds. No fuse can protect a solid state device unless the device was designed to withstand the eternity of time it takes a fuse to blow.
Heat is another killer for solid state devices. Failure lifetimes are exponentially reduced at high operating temperatures. High temperatures enhance conduction mechanisms in SS devices that can lead to avalanche conduction and catastrophic breakdown.
So, if a solid state design is done properly to keep heat down and transients controlled, solid state devices can last for decades. They're lifetime may be dependent on replacement of certain components (like capacitors), which if fail, will take the solid state components with them.
Solid state devices can fail as well, but this is more determined by the original design and support circuitry than the devices themselves. I have Tektronix measurement gear (such as amplifiers and O scopes) that were built in the late 60's and early 70's using the earliest solid state transistors that still meet factory performance specs to this day. That is because the power supplies and bypassing components were of military or high commercial specification, and voltage transients from the power line did not get in and destroy those transistors.
While you can perhaps overload a tube circuit without a big issue, overloading a solid state circuit can spell disaster for a semiconductor. Under certain conditions, overload and secondary breakdown in a transistor is measured in microseconds. No fuse can protect a solid state device unless the device was designed to withstand the eternity of time it takes a fuse to blow.
Heat is another killer for solid state devices. Failure lifetimes are exponentially reduced at high operating temperatures. High temperatures enhance conduction mechanisms in SS devices that can lead to avalanche conduction and catastrophic breakdown.
So, if a solid state design is done properly to keep heat down and transients controlled, solid state devices can last for decades. They're lifetime may be dependent on replacement of certain components (like capacitors), which if fail, will take the solid state components with them.