A navy suit will see you through everything from lunch meetings to summer weddings, so it makes sense to invest in a good one, like Ermenegildo Zegna's. Cut on the 'Milano Easy' block, it's made from mid-weight wool that'll feel comfortable almost all year round. The notch-lapel jacket is kitted out with plenty of pockets and the flat-front trousers are unfinished so you can have them tailored to your preferred break.