You save energy, time and money on a national and international level. Patent searching (specialised literature), scientific articles, trade fair brochures and office databases) helps you avoid duplicate (technical) design and uncovers the current prior art which has decisive importance for novelty and inventive step.
Reliable searches are particularly important in the case of utility models as these are registered at the DPMA without their claims being examined. Any third party can use a cancellation request to have the utility model examined for novelty, industrial applicability and inventive step. This is the same 'inventive step' as in patent law, cf. Federal Supreme Court of Justice in "Demonstrationsschrank", GRUR 2006, 842.