You may have noticed that it was a while since Microsoft released a Service Pack. They keep pumping out Cumulative Updates which include many fixes, but these CUs include a disclaimer that you should only install them if you experience a particular problem corrected by the CU. Several of my MVP colleagues encourage people to install CUs, but I personally find it hard to recommend this to people on a general basis given the disclaimer.
For this reason, Christopher Muthmann, I and Glenn Berry have submitted three Connect items asking Microsoft to release SQL 2008 SP4, SQL 2008 R2 SP3 and SQL 2012 SP2. It's particularly urgent for the two SQL 2008, as they go out of mainstream support this summer.
I like to stress that you should only vote for these Connect items, if you really think that service packs are needed. If the CUs meet your needs, and you don't care about Service Packs, don't vote. Or vote down, if you think that releasing service packs (which requires quite some testing effort) is a waste of time, and Microsoft should focus on improving their cloud story or whatever.
Here are the URLs:
Glenn Berry's, generic for SQL 2008:
Christoph Muthmann's, for SQL Server 2008 SP3:
Mine for SQL Server 2012 SP2:
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se