There have been many questions about apps that do not want to behave with the normal time Schedule of JuiceDefender.
This FAQ will address those questions.
With some apps, like some (HTC) mail clients you do not receive E-mails when JuiceDefender enables mobile data according to the time schedule (e.G. every 15 minutes). JuiceDefender is able to control the Android OS native, built in “autosync” function.
Some apps, unfortunately it is more a couple of, simply use this built in service. It is very easy for programmers to use it! Google provides all programmers with the necessary tools and a simple library.
Still most apps like to use their own, subpar, mechanism for syncing with the server. Usually if an app notices the lack of an internet connection it should simply sleep until the internet comes back on and resume the schedule.
Some apps, like Weatherbug, stop working if no internet connection is detected when they “like” it.
As of now there is no way for JuiceDefender to change the code of all these apps that simply put are not “behaving” like they should. What would you, the users, do if you only receive a sms if you have service when your provider feels the need to deliver it and will never deliver it again?

To put it in a nutshell:

If your app does not use the already built in autosync function of Android and does not respond to the schedules we cannot do much about it. Please ask the coders to change their apps, because it is
a) better and most importantly
b) very very easy for them.

There are some workarounds though that we can offer:

If for example your stock app does not work with the automatic schedule use the peak schedule. You most likely do not need the stock app when the market is closed anyway, so JD can save at least some juice.
If your app allows it, lower the time between schedules, thus increasing the chance for the two schedules to overlap.

If you have any questions please feel free to ask.