Performing the Daily or Weekly Challenges on Halo: Reach are a good way to pick up some extra cR, but sometimes it doesn't pay to "chase" a challenge.  A good example is one of the Daily Challenges from October 12, 2010.

                       

Follow up:

One of the Daily challenges was "Return of the Mack – Kill 50 Elites in Campaign today on Normal or harder" and was worth 3000 cR.  While 3KcR would be nice to get, you have to qualify the time required to get the 50 Elite kills.  During an average game of Multiplayer MatchMaking Team Slayer, a reasonably conservative average is 750 cR per game.  An average MP TS game lasts about 8 minutes.  So to get 3000 cR, it would take about 32 minutes (750÷8=93.75 | 3000÷93.75=32).

During Campaign on Normal, how long would it take to "run across" 50 Elites as well as kill them without too much difficulty?  Even if you start on an Elite-heavy level such as The Pillar of Autumn, it will take time to get to and eliminate 50 Elites.  Would it take longer than 32 minutes?  That depends on how you play and how quickly you can zip through the level.  If you haven't finished the game on Normal, it's a good chance to multitask.  Otherwise, you might get the same points as well as MP stats by playing Team Slayer or some other MP game.

Another Challenge for October 12, 2010 was "Home Field Advantage – Win 7 games in Multiplayer Matchmaking" for 1400 cR.  So you could work on this challenge and average more cR than you could on Campaign: Normal and still be working towards completing a challenge.

October 13, 2010 had a good example as well. The "Headshot Honcho – Kill 11 enemies with headshots in a multiplayer Matchmaking game" for 1100 cR was a bit tough.  Since it says "a multiplayer... game" that means one game.  Considering that a game (Team Slayer) takes 50 kills spread among 4 people, each person will average about 12-15 kills.  That means you have to make almost all of your kills as headshots.  That's a tall order, especially with other weapons and grenades in play.  You could run Rumble Pit to increase the required kills, so that would likely be the best place to do it.

Always look at the Daily/Weekly Challenges and see which ones can be multitasked.  Be sure to have a plan for tackling the challenges, as singles or combined.  And if of the challenges aren't worth the time, why bother.

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