Should original shower drain in 1990s construction be replaced?

[DonLTX]

I’m a basic DIYer with little plumbing knowledge or skills. We have a recurring slow leak in our master bath shower. 1 story home, slab construction so water damage constrained to the one room. Water damage occurs on wall trim several feet away from shower on both piping side and furthest side away. We’ve done a leak test in the pan and plumbers have reviewed and replaced shower values and fixtures while saying no evidence of leak from there. We have regrouted and sealed tile. We have repeatedly recaulked. We may go months without seeing any issues then suddenly bathroom door is swollen shut. Was looking at shower drain assemblies tonight and was wondering about slow leakage in those connections. Should I proactively replace drain assembly from the 1990s? Thank you in advance for your counsel.

 

[Dj2]

"We’ve done a leak test in the pan and plumbers have reviewed and replaced shower values and fixtures while saying no evidence of leak from there"

- So, no leak from the faucet or the pan.
That leaves the under slab drain or water supply pipes as the suspects.
Call a leak detector plumber. It's not a free service, but it will save you money at the end. Using machines, he would be able to pin point the location of the leak.

 

[Sponsor]

 

[Tuttles Revenge]

Can you open the ceiling below the shower drain? Plug the drain and fill the pan then do a bit of dancing around to give it the worst that the shower pan can get to see if that creates a leak. If it doesnt show up either from the gasket seal, or the putty seal, or a crack in the pan, then your problem is further up at the tile or shower valve trim, then potentially a crack in the pipe between the valve and the shower outlet.

Process of elimination starting from the lowest point to the highest.