Funnily enough in NICU none of us were offered sterilisers when we pumped. Nit sure why, but we had to use a touch of washing up liquid and hot water. We sterilised at home but even then that almost lost it's point because it wouldn't be sterile once I took it out and back up to NICU.
None of the 'how to's' in NICU said to sterilise either?
If I was at home and easily able to, yes I would sterilise