Where are you buying them from? Is it Ebay? If it is that could be the reason, when I had my old civic inalways bought cheap Ebay bulbs but they didn't last long either, every few weeks I'd need to replace them.. But good to check your earthing / fuses too Incase!
But for my dc5, didn't want to cheap out so I bought 'MTEC LED sidelights', they are xenon white in colour so goes well with the hid's. Abit more expensive for only wee bulbs at £10-15 but they've lasted me over a year now with no issues!