i was just wondering, when you are planning to build a house, are you able to make any changes to the house plans? is it a hassle to do so?

i was just wodnering, as i have been looking at floor plasn (purely out of curiosity.. we're not buying for a few years yet!) i see a lot ones i like, but i always think 'id rather have this here and this here etc

what about coming up with a plan yourself? i mean the basic layout idea, not so much exact measurement and stuff.

one thing i would like to have is in both 'kids' bedrooms, a WIR. not a hug one, but just more than a sliding door and hanging space.. i know its not a big deal, just something that would work well for me.
also the laundry, one house we rented had a lot of bench space and i loved it! more like a 'room' rather than a pokey little laundry that you cant move in....

just wondering if anyone had done any changes similar??