I feel like it depends in the price for me. If I'm paying regular price and I find a printing defect that's visible, wrong color, crooked engines, etc then I would reject the model and return it. If I'm paying say half price for a model, then I'd be ok with some small print defects or if the color is wrong but within reason. The amount of defects I find on a model should be inversely proportional to its price
For me I’m not too picky on small things like landing gear missing or small paint chips but if it comes to me looking more like a toy than a model that’s when I start to have problems. Especially if I receive it and things like the wings are missing.