How much cropping can an image from a DX sensor take

[BRuke1]

I know there are too many variables for there to be a definitive answer. I'm just looking for a rule of thumb.
A mid-price Nikon DX sensor camera (D3400 or D5600 for instance). With a normally exposed, daylight shot. Can one expect the image to hold up well if half is cropped away? How about if one only retains 25% of the original? I'm talking about seeing the petals on a flower or being able to read the smaller print on a storefront sign, not the point at which the image becomes genuinely pixelated.

[mugge]

Rule of thump 2048 pixels. I rarely go less than 3000 by 3000, or in other words not less than about 8000 pixels in total.
Cheers Ole