In December the base fee was changed due the steep rise in XLM value as answered here. I am looking forward for the next change, and wonder if that's the only reason.
My question is, what is the policy that state what factors are taken into decision to initiate a change of base fee, and for what amount? May it be raised, i.e. if price drops?
Actually, there's an informal official policy:
The base reserve and base fee can change, but should not do so more than once every several years. For the most part, you can think of them as fixed values.
https://www.stellar.org/developers/guides/concepts/fees.html#fee-changes
There is no official policy. When a need arises, the community (of validators) can discuss the issue and decide whether they want to make a change or not.
To answer your other question, the reserve cannot be safely raised. If it were raised, any account with the current minimum would not function anymore.
