I am a fourth year theoretical biology PhD student in a German university. My original funding source has now run out, but my supervisor (who has been quite supportive so far) is willing to fund me for longer, from a separate source. We both agree that if I spend some time there's a good chance that it would result in better quality publications/thesis.
My question is this: if I spend say, five/six years to finish PhD, what are the practical implications I should be aware of regarding staying in academia? E.g. would I face issues applying for postdoctoral positions/grants in EU or US (for eligibility or evaluation)? Is there any major reason to rush and wrap up quickly? Is there some problem I should be aware of and prepare for?