Similar to hotelier reviews, partner recommendations age over time enabling more recent recommendations from partners to be weighted more heavily in the eyes of the algorithm.
Rather than having to go back out to a particular partner who left you a recommendation lets say two years ago and ask them to leave you a brand-new recommendation, one of the features available in the dashboard is that you can send a 1-click update request.
Once your partner clicks the link to update their recommendation, it will count as a brand-new recommendation.