Jelqing is a great exercise working both length and girth...i know a guy gained over 2" in length and about 1" in girth in 3 years doing jelqing only...anohter guy here on
MoS , forgot his name,had a similar workout,doing jelqing only and he got great results...performed corectly,and if you are consistent and don't let your dick turtle in your tight underwear,jelqing can give you great results.
If you're dick is used to some intense routine then yeah,jelqing will not give you amazing results cuz the intensity is too low.