If you’re really concerned about cleanliness insist that the artist use a new needle. Even better, get the model number he/she uses and buy it yourself.
http://s.taobao.com/search?q=tattoo+needle&commend=all&ssid=s5-e&search_type=mall&sourceId=tb.index&spm=a215z.7106357.5803581.d4908513
As you can see, they ain’t expensive. Because they’re so cheap, most legit artists here will be happy to oblige you. The professionnalism has improved markedly here in recent years.