I've been using my sterilizer for 5 months and it has what looks like rust at the bottom. Should I buy a new one already?!

You might need to descale your steriliser with citric acid. Remember to switch off the power supply before descaling. http://www.p4c.philips.com/cgi-bin/cpindex.pl?ctn=SCF274/23&dct=FAQ&faqview=1&refdisplay=AVENT_EXPRESS_STEAM_0003&refnr=0070496&scy=GR&slg=ENG

You can use citric acid (I bought from Phoon Huat at less than $3) and do a one cycle of sterilising. Leave it there for 30mins and pour away the water will do the cleaning trick. I clean it once a month.

thanks