Blocking site to Google

I'm in the middle of developing my site. Google has already started to index it. If I prevent googlebot from indexing my site then:

a. How long should it take before I am removed from the index? (next crawl I guess)

b. When I finally finish developing my website and decide to re-allow google to crawl my website how long will it take to have my site indexed?

Is there a difference between the time taken for Google to index a site when it's new and when it was previously indexed but subsequently blocked? (Maybe googlebot doesn't check the site as frequently when it knows a site has been blocked)

Please note: you'll only get it deindexed if you use the <meta name="robots" content="noindex, noarchive" > command. Next crawl maybe Don't be tempted to use robots.txt .... if googlebot doesn't crawl your pages, that doesn't mean the pages will be deindexed. Especially not if there are links (any links) pointing to it.

@ b. That depends on how many links you'll point to it at that stage.

I would not worry too much about being indexed before your site is totally completed. It, your site page(s), will likely not be in the top of any SERPs without backlinks AND being indexed starts the clock on site age.

No sense in not being indexed as SEO AM says. Award yourself one backlink from an indexed site and start that age clock on your site ASAP.

Wow, your advice just came in the nick of time! Thanks, everyone.

On a related note, does Google consider php errors as spammy content? My guess is that it might if there's enough of it around. How forgiving is Google for this type of content? There must be millions of sites out there that Google comes around to at an unfortunate time...when a server is down, when a new error occurs, when somebody spams the message-board etc.