We bought some of these based on a Wirecutter review, and I was really impressed. Cold water with a lot of ice stayed ice-cold all day. The ice was still cold at the end of the day, or in the morning if I filled the bottle with ice water and set it on my bedside table to sip overnight. After graduating from 14-oz and 18-oz bottles, my kid now takes one of these bottles in her school bag every day. If we put in too much ice on a cool day, the ice will stay so cold that it accumulates into a large chunk. It stays that cold! On hot days, we fill these bottles with more ice, and that helps keep everything cold even while this bottle sits in the direct sun at the beach or a park.The lids are dishwasher safe, and the small white gaskets inside the lid and the spout lid are seated pretty well, but we did lose one gasket. You can buy replacement gaskets directly from Takeya (they also run regular deals on these bottles, but in this instance I found them cheaper on Amazon and needed them really quickly). They have two different gasket styles; the better and I think newer ones have a small circular tab (almost a loop) that does double duty in helping you insert/remove the gasket and also seems to keep the gasket seated better. I say that because the one we lost did not have the tab.I check our gaskets regularly and they seem to be quite impervious to mold. I pull them out every 4-6 months to inspect and clean them, and they are always fine with no visible signs of mold.The one con to the bottles is that they get dented when you drop them. If you have a kid who swings their bottle around (and who wouldn't want to do that with the really great loop integrated into the lid of this bottle?), over time the bottom will reshape itself from flat to curved. Eventually my kid dropped the bottle or bashed it into one too many hard surfaces, and one of the dents broke full through. Then the outside of the bottle had a hole in it. The inside was still fine, but after hand washing the bottle, there was water inside the lining, and I don't want to risk that becoming a moldy mess. That's why I needed to replace a bottle.We had our bottle for about a year and a half before the r outside split. That's an expensive habit, so now I am making sure my kid keeps the bumper on the bottom -- and refrains from swinging the bottle around so much.We love our Takeya bottles! I liked their performance so much that I bought two for myself and rotate their use daily. Since we only put water in them, I put the lids in the dishwasher every day or every other day, and leave the bottles to dry in our dish rack nightly. I hand wash them with dish soap and a brush a few times a week. The only spot you have to be careful to catch is under the stainless steel rim below the lid, which is a narrow channel that can harbor some sand or dirt (and other gross stuff).The one on the left in the photo has been used for about 18 months, and the one on the right is brand new. I made large name labels for all of them with permanent vinyl, which you can see in the older bottle has scratched off in some places. I believe I re-applied the label on the left in the last six months, so keep in mind that Cricut "permanent" vinyl is not going to last forever on a curved surface like this that gets used and banged around every day.