An efficient way to store monthly recurring data that does not change frequently?

I'm trying to find an efficient way to store monthly recurring data that does not change frequently.

class Fund < ApplicationRecord
  has_many :factsheets
end

class Factsheet < ApplicationRecord
  belongs_to :fund
end

A Fund will have a new Factsheet per month.
Each Factsheet have an objective on it (very long text, suppose).
The objective may change each month, but not frequently (say, change once per ~10 months).

Any good way to store the objective?

Option 1:

Put objective into model Factsheet, and it will duplicate a lot.
(store 12 objectives for 12 months, but most of them may be exactly the same)

Option 2:

Make objective a model, then Fund has_many :objectives

class Objective < ApplicationRecord
  belongs_to :fund
end

Objective will have a column :effective_on to indicate: from which month a Fund should use this Objective record on its Factsheet.
(store 2 objectives for 12 months if only changed once)

Option 3:

Better idea?

I would go the simplest option in your case, which is the first one.

Now why? My motivation is scale. Option 2 is a common case of over-engineering in my view. You'll have roughly 1200 records on one table in 100 years, and let's assume for the sake of the argument that the objective never change: you'd get 1200 entries in the DB that are duplicated.

Is that a big deal? I think not. For this scale, I believe a bit of duplication is perfectly tolerable.

If you were to create an entry every second, we could argue for a better solution, but I'd advise you to go with the simplest solution and concentrate on a problem that really does need some well-engineered solutions :).