How long does paint from a spray can last?

[m3e92]

hi all, im new here. Im really urged to spray paint my car using Duplicolor MP403 Red/Blue Mirage Kit. Problem is I live in Singapore and its hot in here and it rains often, will the paint wear off and become 'sticky' easily? And will it ''de-gloss'' itself after a while? I intent to spray paint about 15 coats to give a shine. Its a 350z/Fairlady roadster, any advice on how to do it without damaging the softtop? Thanks all