Is it permissible to combine the invocations (adhkar) for waking up and those for the morning, as well as combining the invocations for sleep and those for the evening, due to circumstances of sleep and work?

Firstly, it is best to recite each remembrance (dhikr) at its appropriate time, such as the remembrances of waking up when one awakens, and the remembrances of sleep when one lies down. This is evident from the hadiths. The morning remembrances are recited between the appearance of dawn and sunrise, and the evening remembrances are recited between Asr (afternoon) prayer and sunset. If the evening remembrances are delayed until bedtime, and they are recited before midnight, they are still considered evening remembrances. Similarly, if the morning and waking-up remembrances are combined when one awakens from sleep before midday, they are considered morning and waking-up remembrances. However, the best and most preferable approach is to recite each remembrance at its designated time.