We use them every time we travel. I have several different sizes and sort according to style of clothing, i.e., underwear in one bag, pants in another, shirts in another, ... and I put my pillow in a bag. I also have one large bag in the front pocket of each of our check-on luggage. When we reach the airport, we take off our coats and put them in the bags, compress the air out, put the bag in the front pocket of the luggage ... when we reach home (snow country) our coats are easy to pull out and have available.
Since our items are sorted and visible we have never had a problem with TSA opening the space bags.
When we are in the hotel, we keep a bag in the bottom of the closet for dirty clothes. When the bag is full, I compress the air out and pack the bag. When it is time to go home, most of our packing is already done.