For protection against loud environments, custom-moulded earplugs are excellent — the best single investment a tinnitus-aware music lover or motorcyclist can make. They are taken from an impression of your ear canal so they seal properly, and the filter cartridges typically attenuate sound by a flat 9, 15, 20 or 25 dB across the spectrum, meaning music still sounds like music, just quieter. Cheap foam plugs work too, but they muffle the high frequencies disproportionately and most people find that unpleasant enough to take them out.
For everyday use, however, custom-moulded plugs are usually the wrong tool. Wearing them in normal-volume environments — cafés, supermarkets, offices — because of hyperacusis or anxiety about loud noise tends to deepen sound sensitivity over weeks. The auditory system reads a quiet environment as a quiet environment and turns its gain up.
A reasonable rule: wear them when sound levels genuinely exceed 85 dB SPL — concerts, power tools, motorbikes, nightclubs, hairdryers near the head. Take them out for everything else.