Always initialize variables that might be nil to appropriate default values to prevent unexpected behavior. For boolean flags, explicitly initialize to false in constructors or initialization methods: ```ruby def initialize @unsubscribed = false # Clear and explicit boolean state end ``` For collections, initialize to empty arrays or hashes rather than nil. When setting defaults, use `||=` or `Hash#reverse_merge!` to assign values only when current value is nil: ```ruby @options[:autocomplete] ||= "off" # Only assigns if nil # or @options.reverse_merge!(autocomplete: "off") ``` When implementing predicate methods, use explicit `== true` comparison to ensure they return true or false, never nil: ```ruby def define_predicate_method(name) define_method("#{name}?") { public_send(name) == true } end ``` For complex types like JSON, provide sensible defaults: ```ruby # When handling JSON type when :json then {} # Or use a more descriptive example structure ``` This proactive approach prevents nil-related errors and ensures consistent behavior throughout your application lifecycle.