more exposure = more density.
if darkroom printing it typically just means longer printing time unless you are way up in the shoulder of the film.
for scanning, it’s generally not an issue, but you do want to be careful about retaining enough discrete tonal values per stop of exposure or your highlights will look very chunky. Depending on the scanner, where that point is will vary, so it’s generally good practice to keep the negative density range relatively low. This is why many people say a thin negative scans better. It’s all about maintaining as many discrete tone values as possible per stop of exposure. Also, depending on the scanner, if you start to get too much density, the scanner will introduce noise from the digitization into the highlights which will make them look chunky as well. Where that happens will vary quite a bit depending on the scanner. Some are very clean, others might say they’re 16 bit, but you really only have 11 or 12 bits that aren’t loaded with noise. In that area more money does generally buy a better scanner. For negatives, you generally want to have a very clean 3.3 to 3.6 log of available tonal range as a minimum. More is better, but if your scanner is 16 bit and has low noise in the 65535 to 32 number range, you’ll be fine as long as the negative fits in there with the highlights not going below 32. A well exposed and developed negative is generally quite a bit less than 2.7 log density range, so usually it’s not so much a problem.
this is for black and white. Color is similar, but more complicated.