When to get new insulin...

OK, reading the leaflet in my bottle of Lente insulin for my cat, it says it should be replaced every 4-6 weeks...Ive been doing this, and my vet has advised me to do so, but a freind of mine who is also a vet (though not treating my animals) has said this is un-necessary adn is costing me too much moeny. Who should I believe...

Also out of interest those of you that haev diabetic cats, what dosage are they on? (Uk only please, I get confused with the American measurements! lol)

Tiffy is on 2x8 units a day

Angie
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