In-Game Parser.

[Atomnium]

/supporting official ingame parser.

A parser should be a mandatory starting point for any player (and later a well needed friendly tool), it could show your weakness and force yourself on self-improvement against various enemies during your learning path.
The way you will dodge in X fight or learn to coordinate your movements will then be based on the training you dedicated to your DPS, so you better start with solid bases.

Keep in mind that parsers are not cheating tools, a parser will not do the work for you, it doesn't think, it will not teach you how to dodge, it will not tell you when using a specific CD at a precise moment, it doesn't forgive your mistakes.
It will just show you a possible weak spot within your gameplay in order to solve it by your own.

If there was no DPS check fights in FFXIV, I would say... As long that your rotation is correct and you do fine with dodging / movements, we could be like "eh, who care, let's keep it this way"
But that's not the case, FCOB and some other trials proved once again that tight DPS check fights are a strong and important point when the DEVs are actually designing contents. A parser is a necessity in your learning progression for them.