Despite the increasingly common use of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies in treating CF, it is still largely unknown whether or not other chronic therapies can be safely stopped. The SIMPLIFY study is being done to test whether or not it is safe to stop taking inhaled hypertonic saline or Pulmozyme® (dornase alfa) in those people that are also taking Trikafta™. Trikafta (elexacaftor/tezacaftor/ivacaftor) is a combination CFTR modulator therapy that was approved by the Food and Drug Administration for people with CF who have at least one F508del mutation. The three drugs that make up Trikafta work together to allow many more chloride ions to move into and out of the cells, improving the balance of salt and water in the lungs. These changes result in better clearance of mucus from the lungs and improvements in lung function. Inhaled hypertonic saline and Pulmozyme (dornase alfa) also improve clearance of mucus from the lungs to support lung function and have been available to people with CF for many years. Both therapies are considered to be relatively burdensome and it is not known whether either therapy can improve or maintain lung function above what is already gained through Trikafta use. The goal of the SIMPLIFY study is to get information about whether or not it is safe to stop either inhaled hypertonic saline or Pulmozyme (dornase alfa) by testing if there is a change in lung function in subjects with cystic fibrosis (CF) who are assigned to stop their chronic medication (either hypertonic saline or Pulmozyme) as compared to those who are assigned to keep taking their medication while continuing to take Trikafta.