Only you and your doc can answer that.Usually glucose acceptable range starts from 4/72;and advice to treat as hypo below that level speaking personally I do not use my insulin if below 4/72.I treat with 15g carbs,test 15mins later.keep repeating til above .Eat!
I am type 2 and still produce some insulin.it may be different for you as a type 1.( Even then you may be producing a little insulin )