coalescent ward vs preservation wards

[PRO_EGERN]

What is more worth it one coalescent ward or 99 preservation wards, they cost almost the same?

[Adinos]

A coalescent ward costs the same as 100 Preservation wards. Therefore you should use a preservation ward when you expect to need fewer than 100 on the average.

In other words:

Use a coalescent ward when you have a 1% chance of success ... in any other case use Preservation wards.