If the culture you want to maintain is "first 10 minutes of every meeting is everyone reading the agenda" or "thorough security review for all changes before go live" then you want slow turnover so new hires can be trained and indoctrinated.
On the other hand if the culture you want to maintain is "constantly be trying out new technologies, new ways of working and fresh ideas, at the cutting edge nothing is set in stone" you might benefit from new employees who know firsthand how other companies solved whatever problem you're facing.
On the other hand if the culture you want to maintain is "constantly be trying out new technologies, new ways of working and fresh ideas, at the cutting edge nothing is set in stone" you might benefit from new employees who know firsthand how other companies solved whatever problem you're facing.