5 Kakaars have individual significance, they are kind of reminders, but if one does not understand the significance and wear them just to satisfy ego(I wear kakaars-I am better sikh) then its of no use.
To me:
1. Kesh - Remind us to be happy in what God gives us
2. Kanga- To maintain and take care of what God has given us.
3. Karha- To remind one should never do wrong things with there hands, to do kirat with their hands and to help others with their hands.
4.Kirpan- Save yourself and save others from injustice, be alert against your own mind and ready to fight with it.
5.Kachera- Be strong and control your lust, take care of your personal hygiene.
there could be more to it but if one can reach the stage where he/she can remember these things without reminders, then there is no need of Ks.
Above reminders could be helpful in our spiritual journey but they alone wont take us anywhere.