There are risks to building in house too: Things will break over time Key programmer leaves, no good documentation or succession plan left behind New needs will arise (e.g. if you built an expense tracking app before smartphones, you'll now need to build a iPhone/Android app) Maintaining security - is your security team really better than the outsourced service's? API support Developer ecosystem

There's always a build vs. buy decision and sometimes you should build, but this is why even huge companies use Salesforce over maintaining an internal CRM.