Well I guess I will weigh in here. Normally I have 3 going at a time. Right now I cleared my workbench off ( I know a mortal sin) and have a Huey 1C in the works for a co workers father. He is a Viet Nam Vet who was a pilot in command of a Huey 1C in the late stages of the war.

So at this time that is my only project.

Normally its one at a time,but right now im doing 2, but one of them was already 90% complete when i started the new one

I've lost count of the "Started" ones.....25-30 atleast..

There's a few i'm concentrating on to finish up... before starting new ones........

I tend to lose interest in one particular model rather quickly (ie. once it looks like a tank, minus all the do-dads, I usually set it aside). Right now I have Trump 1/16 T34, 4 Tamiya R/C 1/16 tanks (Tiger I, II, Sherm, Pershing) Dragon Panther A, Abrams OIF, M113 Desert, and a Ferrari F1 2001 (i know its a car, but I'm a car guy too!!) Due to the fact I have only completed 3 models in 4 years, I need to concentrate more, and finish some! My problem is I hate painting them!

One at a time. I try to finish a model before beguining an other one.
But sometimes events decide for you ! No more paint or the resin kit you've ordered is not arrived yet !

But never more a couple of project in the same time

One at a time.