help wit sizes

for those who be rockin dem Redmonkey and Evisu jeans, how do they fit. i usally wear a size 34 size 36 depending on brand. i bought a pair of Redmonkey jeans from this shop around where i stay and they where size 34 and they fit perfect. but i ordered a pair jus resently a size 34 and they fit different. the quility was perfect but they fit slim and longer....do they fit different in models or what