Each placement is given a heat bonus, equivalent to its qualitative score, that diminishes over time. The impact of the heat bonus decreases after your top 5 placements (for more information on how the qualitative score and heat bonus work, see How Does the Ranking System Work?)
Because of the decreasing impact, submitting to lots of competitions at once won’t necessarily improve your ranking. However, placing in one or two competitions once your heat bonus diminishes can help your project stay relevant and maintain its rank.
Badges earned can never be lost so they will always show how well your project performed, even as you move on to circulating the next one.