I love buildings built in the 1920s, but I rarely buy buildings built before that.
It has to do with how the buildings were built.
By the 1920s, Los Angeles construction practices were not that different from today’s. Layouts, door width, ceiling height, spacing between studs, size of lumber used – all are quite similar to how we do things today (or better).
Prior to the 1920s, however, there was a lot more variation in construction practices. Some buildings were well-built; others are janky. They have illogical layouts, narrow doors, low ceilings, irregularly or widely spaced studs, and make use of thinner, weaker lumber.
As a renovator, the building you buy places meaningful constraints on the finished apartment product you can deliver. And the constraints created by pre-1920s buildings generally tip the scale against doing those projects.