If one is going to take his talis katan off for a long period of time (around an hour) which situation would be best?
a)When making the bracha in the morning, have in mind the bracha should last the whole day
b)When making the bracha in the morning, have in mind this will last only until they are taken off and then make a new bracha when putting them on again.
c)Put on a different pair and make a bracha
If C is not an option (if one doesn’t have a spare pair available), would A or B be better?
Having in mind the bracha should last the whole day does not overcome the problem of a hefsek. An hour is questionable if it constitutes a hefsek, so having in mind in the morning that the bracha should only last until such a hefsek is made would be preferable [see Biur Halacha 8:11].