How off-center is too off-center for a drain on a new shower base?

I was in almost the same spot two years back with a Kohler base we set over an old cast iron rough-in. The pipe came up maybe three quarters of an inch off center and I talked myself into letting it ride because the screws bit and nothing dripped during the first fill test. It held for about a year, then I started finding a damp ring on the ceiling below after long showers. Turned out the gasket was squeezed thin on one side and thick on the other, so it seated crooked and wept slowly every time water pooled around the strainer while the pump of the shower ran.

What I learned the hard way is that the test passing on day one means very little. These connections fail slow, not fast, and by the time you see it the damage is done. If the installer is the same crew that rebuilt that line anyway, the labor is the expensive part and they are already standing there with the tools. Cutting out and redoing a connection that was done wrong is a fair ask, and any decent installer will own it without much fuss. I would at least take some photos now and keep an eye on it monthly, but honestly if it were my house I would make the call today and have them come back before the wall board and tile go in. Once that access closes up, the redo gets five times more painful.

I'd push for the redo, but that doesn't mean tearing everything out like you might be picturing. When our GC set a DreamLine base in my mother-in-law's bathroom, the drain landed about an inch off because he reused the old tub location without checking the rough-in first. What fixed it wasn't a full demo. He pulled just the base, cut the stub back, and added a small off-center fitting so the pipe came up true, then reset the pan. A full afternoon of work, and no drywall dust in the rest of the house. The thing about an inch of offset is that the strainer ends up sitting cocked even if the screws catch. That's exactly the setup where water sits against one edge of the flange and finds a path through the putty or gasket over time. The screws biting is not the test people think it is, because a drawn-down flange will hold tight on day one and still wick water two years later. Also worth thinking about is who pays if it leaks. If the installer left it off-center, that's on them, and getting them back now while the job is fresh is alot easier than calling them in eighteen months when your floor shows a stain. Contractors genrally respect a customer who catches this stuff at walkthrough.

Seconding the reply about just reworking the stub instead of any big demo. When my brother's base went in off center, the plumber came back and reset the whole thing in under two hours because the base hadnt been tiled around yet. He just pulled it, trimmed the pipe, and used a coupling to get it dead center. Cost my brother nothing since it was thier mistake. Call now while everythign is still open, after the tile goes down the same fix turns into a week of mess.

I redid a similar offset in my own bathroom last summer and the thing that actually made it work was a no-hub coupling with a center stop in it, because the pipe kept wanting to drift sideways while I torqued the band clamps down. Got it dead centered first try after switching to that. One thing I'd add is to check the base itself for level while they've got it pulled, since mine turned out tilted from the install and no centered pipe fixes water pooling at the strainer. Run a hose test for a few minutes after the redo and just watch the edge.