There are many epic threads that discuss what you're asking. To summarize them: YES NO MAYBE DEPENDS!
What your store is telling you will produce beer. The one thing I can say personally, is that being patient improves my beers. When I leave my beers in the primary for 2-4 weeks, bottle, wait 3 to carb, then lager them for a month, they always taste better than when I rush it.
Regarding secondaries - I don't use them. My reasoning is that I'm lazy, it increases chance of bad sanitation, and there is lots of anecdotal evidence from very successful brewers that it doesn't really help (outside of exceptional cases like long term bulk aging).
Try it both ways and see what you like!
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edit - see, leave it to Revvy to not be lazy and actually post the link. Thanks Revvy.