Compare Budz at 4 weeks to Harvest Time

How big of a difference in bud size is there at the end of 4th week flowering compared to harvest time?

I realize different strains have different times and will show different things but in general what kind of size change should I be looking for..

I mean, are the calyxes much bigger, are there more trichomes, should it get longer or thicker, etc....

The more input from various strains the better.... I am 5th week of first grow with some swag seed to get everything tuned right and was just wondering if the buds change drastically from the 4th week to harvest.

I should harvest in a week or two.
You could check my journal for picture.

I grow 10-11 week strains (should be 9 weeks, but light problems elonged the proccess) and I usually except the buds to double in size in the last 4 weeks. At least double.