Your stairlift and rail should be wiped down and dusted every month or so, we actually recommend using the likes of "Mr Sheen" on the stairlift rail as it prevents dirt sticking to it and can help the rollers last longer.
Apart from that we do recommend getting your stairlift serviced every 12 months to ensure it's operating correctly and to see any potential issues that could be developing before letting it deteoriate.