Breastpump

Planning to try breastfeeding, and if successful will need to breastpump when I go back to work. Anyone planning to use a "USED" breastpump?? Both of my SIL gave me their Medela in style electric pumps. I have done some reading and it sounds like Medela pumps are meant to be used by one person only due possibility of milk/bacteria collecting in a space that can't be sufficiently cleaned. Just wondering about anyone else that has used "USED" pumps that has any experience with this?