The Haynes manual for 1989 to 1995 Fiesta's says the Ford spec fluid ESD-M97B-49-A is lifetime. See below. The 2 to 3 year change interval was for coolants of a different specification.
Since then, ESD-M97B-49-A was superseded by WSS-M97B44-D.
WSS-M97B44-D is Ford Orange in the US.
In Europe, Ford say WSS-M97B44-D is a 10 year coolant for all European manufactured vehicles:
Note that in the US, the Ford Orange / WSS-M97B44-D coolant has been replaced by Ford Yellow which is apparently the Prestone 10 year coolant!
Antifreeze - notes on renew
24 Ford state that, where antifreeze to Ford specification ESD-M97B-49-A is used, it will last the lifetime of the vehicle. This is subject to it being used in the recommended concentration, unmixed with any other type of antifreeze or additive, and topped-up when necessary using only that antifreeze mixed 50/50 with clean water. If any other type of antifreeze is added, the lifetime guarantee no longer applies; to restore the lifetime protection, the system must be drained and thoroughly reverse-flushed before fresh coolant mixture is poured i
25 If the vehicle’s history (and therefore the quality of the antifreeze in it) is unknown, owners who wish to follow Ford’s recommendations are advised to drain and thoroughly reverse-flush the system before refilling with fresh coolant mixture. If the appropriate quality of antifreeze is used, the coolant can then be left for the life of the vehicle
26 If any antifreeze other than Ford’s is to be used, the coolant must be renewed at regular intervals to provide an equivalent degree of protection; the conventional recommendation is to renew the coolant every two or three year
27 The above assumes the use of a mixture (in exactly the specified concentration) of clean, soft water and of antifreeze to Ford’s specification or equivalent. It is also assumed that the cooling system is maintained in a scrupulously-clean condition, by ensuring that only clean coolant is added on topping-up, and by thorough reverse