Very sorry to hear that you are having problems, Ali and funkychips. Growing condition is different for every one, but most agree high humidity level is very important for most nep species. In northern peninsular Malaysia, it's very dry, hot and windy now, so no surprise I have some neps that's more fussy refuse to pitcher or the new pticher bud dried out. In the meantime, some hardier neps just keep on growing and pitchering like nobody's business...
Don't be too hard on yourselves. Just think about it, even in nature, during certain period (changes in weather pattern), even wild neps will not grow well... They just stop producing pitchers and the growth will slow down, adapting to the changing weather.
Just to check, did you use same type of soil/media for all your neps?? I tend to adjust my mixture according to the species of neps and try my best to simulate it's original growing habitat.