Confused about sterilising bottles

CL

Hi I'm pregnant with my first baby and planning to breast feed but I also want to pump and use bottles. I'm a bit confused about electric sterilisers. They say the bottles will stay sterilised for 24 hours if the lid is unopened. But if you get 1 bottle out the rest then need to be resteralised? Whats the point in sterilising multiple items if you have to sterilise every time you get something out of the steriliser?

I’m confused!