Ask which feature the viewer needs
Captions, ordinary subtitles and audio description serve different needs. A dialogue subtitle track may omit information about other sounds. Audio description adds spoken information about visual action. Ask for the specific language and feature instead of assuming any text or alternate audio track will do.
Test the actual viewing setup
Open the title on the television or device that will play it. Find the desired track, then play a short passage with speech, music and visual action if possible. Ask the viewer to try their usual seat. Readability can change with text size, background, distance and the part of the screen covered by captions.
Have a useful second choice
Keep a second title with verified access options. If an available caption track is hard to read, try the device’s text size or contrast settings where available. Ask the person using the feature what works for them instead of treating a listed track as proof of a good experience.
Write the verified title, service, device and track together so the group can return to the same setup. If a feature that appeared on a phone is unavailable on the television, choose a workable device or the backup title. Check with the viewer before telling the group the access problem has been solved.