What is a balanced collection?

Discuss the pros and cons of buying bundled sets of resources, for instance a journal database or a Standing Orders service.
Pros
Free up time.
inexperienced or new TL able to resources a library due to the simplicity of obtaining resources
resources are screened
Reputable publishers and popular authors
Age suitability
Discounts
Continual supply
Wider variety of fiction types, horror, fantasy

Cons
Some double ups on titles.
Not meet the interest of students.
Issues may arise with regards to platforms if bundling ebooks and limitations to specific devices.

Consider also the pros and cons of selecting content that is provided via online access but which the library does not own.
Pros
Physical storage space not required
24/7 access
Initially cheap as you may not have to buy outright and allows for review and analyses of resource.

Cons
Access to online resources might be problematic for some.
Over time may be expensive for renewals of subscriptions

I am interested to read the ideas of others as I have only produced a limited list of pros and cons which reflects my inexperience.