Quarantine Tank !!!

[jack]

hello guys,

i was going through forums and sites and found a mix reviews about setting up a Quarantine Tank. soo here my question is

1) is it necessary to set up quarantine tank ??
2) if yes then how big should be a quarantine tank ?
3) how many of you (reefers/marine world hobbist) have kept quarantine tank ??
4) is it necessary to quarantine each fish before introducing to display tank ?? (the fish i will be getting will be quarantined and will be captive breed)
5) have read on plenty of site about freshwater dip to marine fish so that all the external germs die off, does anyone practice this method ??

Thanks for reading and answering.