I am wondering if there's a more elegant way to say this in Ruby:
FREE_PLAN_MAXIMUM = 1 BASIC_PLAN_MAXIMUM = 10 PREMIUM_PLAN_MAXIMUM = 100 def maximum_entries_per_month case plan when "premium" PREMIUM_PLAN_MAXIMUM when "basic" BASIC_PLAN_MAXIMUM else FREE_PLAN_MAXIMUM end end I don't like the repetition of premium and basic inside the function. What might be an alternative?
It depends on the rest of your code, especially whether you're using those constants in other places. One pattern I've found nice for this kind of thing is a hash, though.
PLAN_MAXIMUMS = { free: 1, basic: 10, premium: 100 } def maximum_entries_per_month PLAN_MAXIMUMS[plan.to_sym] || PLAN_MAXIMUMS[:free] end 
PLAN_MAXIMUMS.default = 1 and just PLAN_MAXIMUMS[plan.to_sym] would also work.Use Hash#fetch, which allows for a default value, instead of a case statement.
PLAN_MAXIMUMS = { free: 1, basic: 10, premium: 100 } def maximum_entries_per_month PLAN_MAXIMUMS.fetch(plan.to_sym, PLAN_MAXIMUMS[:free]) end You don't need a method. Just have a hash:
maximum_entries_per_month = Hash.new(1).merge{"premium" => 100, "basic" => 10} and call:
maximum_entries_per_month[plan] 
what about:
FREE_PLAN_MAXIMUM = 1 BASIC_PLAN_MAXIMUM = 10 PREMIUM_PLAN_MAXIMUM = 100 PLANS = {'premium' => PREMIUM_PLAN_MAXIMUM, 'basic' => BASIC_PLAN_MAXIMUM, 'free' => FREE_PLAN_MAXIMUM} def maximum_entries_per_month PLANS[plan] or FREE_PLAN_MAXIMUM end that "or FREE_PLAN_MAXIMUM" will catch any plan that's not "premium", "basic" or "free", if you are sure you only have those three plans just remove that part
EDIT: this way you keep your other constants working
EDIT2: if you don't want to add more constants and you are sure plan is one of those, you can do:
def maximum_entries_per_month self.class.const_get("#{plan.upcase}_PLAN_MAXIMUM") end 