A deuterated solvent can impact whether exchangeable protons, such as OH or NH, are visible on a 1H NMR spectrum. The advantage of eliminating any contribution from an exchangeable proton(s) is to simplify spectral interpretation. One disadvantage of not seeing exchangeable protons is the deficiency to the total proton count in establishing the molecular formula.
The diagram below compares two 1H NMR spectra for the same functional group in two different deuterated solvents. The 1H NMR spectrum in deuterated-DMSO shows two doublets whereas the spectrum acquired in deuterated-methanol shows only the singlet for the CH group.