How do you decide between using a third-party Django package and writing the functionality yourself?

Treat it as a cost decision. A Django package is not free — it constrains your upgrade path, and an abandoned package can hold you on an old Django version for years.

Use a package when: the problem is well-defined, widely solved, and dangerous to get wrong. Django REST Framework, django-allauth for social login, Celery for task queues, and django-storages for object storage all qualify — you would not want to reimplement any of them.

Write it yourself when: you need a fraction of what it does, or when the package imposes an abstraction that fights your models.

What to check before adopting:

• Does it declare support for your Django and Python versions, and how quickly did it support the last release?
• How many open issues, and when was the last commit?
• Does it add migrations or middleware to your project — those are hard to back out of.

Note: Django's own contrib apps should be your first stop. Candidates regularly reach for a package for something the framework already does.