Fig.: to be very precise and meticulous down to the smallest detail

When dealing with John, just be careful and make sure you have all the Is dotted and the Ts crossed, as he tends to be very lax

Giovanni è un facilone, e se vuoi lavorare con lui devi stare attento a mettere sempre i puntini sulle “i”

After they had done the first draft of the contract, the lawyer went over it with a fine-tooth comb to make sure that all the Is were dotted and the Ts were crossed

Dopo la prima stesura del contratto, l'avvocato l'ha riguardato fin nei minimi particolari per assicurarsi di aver messo tutti i puntini sulle “i”

The phrase, which has been in use since the 1800s, is said to be originated from the possibility of confusing Is with Ts if they are written without the respective dot and cross