Over time models may need repair because of wear. For example, bearings can wear out, and steam locomotive rods can become worn to the point that the locomotive will not run without binding. The plating can wear off from plated tires allowing the underlying brass tire to wear to the point where it needs to be replaced - I fabricate replacement tires from 12L14 (LedLoy) steel.
Accidents happen, and models get bent. Solder joints can fail.
You may acquire a locomotive that won't run well if at all. Replacement of the motor may be sufficient to get the loco running. Or you may want its details upgraded or modified to represent a specific prototype.
You may have changed your modeling focus, so certain favorite models don't "fit" your scheme anymore. You might want to have those models modified to fit your new scheme. In general, if you don't like some aspect of your model, the model can be changed so that you like it.
You may decide to convert your layout to Digital Command Control (DCC), or you are building a new layout and want to use DCC.
In lieu of my listing what can be done, please see Completed Projects for descriptions (and eventually, photos) of repair and upgrade projects I have completed.
If major paint work is needed as part of the repair, the alternatives will be presented to you for your choice. Alternatives can range from you preferring to perform the paint work, to me outsourcing the paint work to a trusted painter, to having me take care of repainting the model.
It is possible that during the course of making the repairs/upgrades other items needing attention will be noted, and that I will recommend to you that additional work be done. This is done in the interest of your finding a high quality satisfying model when you open the box, not in the interest of making work for me, since I have plenty to do.
Please see the warranty description under the WARRANTY button.