I've played Fire Emblem: Awakening but I never paid close attention to either of these two seals.

So with Fire Emblem: Birthright I haven't upgraded anyone's base class yet nor have I re-classed any units yet. That said, I was wondering when's the 'best' (if there is) time to use a Master Seal on a unit? I've heard around level 15 but I remember people telling me level 20 for Fire Emblem Awakening. If level 15 is the best time, why?

Also, is there any purpose to re-classing any units? I can only think of a handful of units I'd re-class (i.e. the lower levelled units I don't use much in battle, who I could better re-purpose, like Hayato.

In general, you want to wait until max - level 20 - before promoting units with the master seal. I remember promoting my healers early in Awakening because leveling them was such a pain, but try to hold out.

When you promote, that unit reverts to level 1 (in their new class), but it's really more like they skip straight to level 21. The game will not simulate anything in between. So if you promote at, say, level 15, you're throwing away 5 level-ups - and 5 chances to increase the unit's stats. Since in FE, a single stat point can make a difference, a too-early promotion can have a noticeable effect on a unit's effectiveness.

@encephalon:Oh okay. So, you mean if I promote at level 15, I'll miss out 5 'level ups' worth of stats increases (+1 Strength, +1 Magic, etc), correct?

I have quite a few units still hovering below level 10. I'm on Chapter 13 and haven't done any of the challenges/scout missions either. I haven't really felt the need to so far, but I guess I might to level up units I don't use as frequently - unless I can re-class them early?

@haz: In Awakening you could promote units essentially whenever, since Second Seals drop you back to level 1 and effectively give you infinite levels. In Fates, Second Seals (or Heart Seals, Partner Seals, etc.) retain your current level when you reclass so you don't have to re-level characters. However, this means that you can no longer reclass over and over and have infinite level ups. This is why everyone will tell you to wait until level 20 to promote. If you promote at 15, that's 5 levels worth of stat ups that you just missed. Also, EXP gain is based on a unit's level in Fates. A promoted unit is essentially level 21+. If you promote early, you are potentially gimping that unit's EXP gain when it could have still gotten 15 or 30 EXP for a kill instead of just 1.

As for why to reclass, the main reason is to learn new skills. A lot of units benefit greatly from skills that are not on their main line and it's smart to have a wide variety. Some units have stats that fit other classes better or their level ups have suddenly made them a tank or a high strength unit that they could take better advantage of in a different class. Also, enemies tend to carry (at least on Hard and Lunatic) a lot of weapons that do bonus damage to specific units. Maybe you want to use Silas but you're scared of beast killers, or maybe you really like Hinoka but archers are a constant annoyance. Reclassing can solve those problems and on higher difficulties, can save those units. Now if you're just going through something like Birthright casually, you don't really need to worry about reclassing unless you really want to or plan on spending a lot of time with the game. It's mainly for learning new skills and applying an extra strategic element to the game.

Reclassing serves to:

-Bring more variety to your party I.E. getting more Great Knights for a more mobile army.

-Getting new skills. Reminder that any skill you missed out on will be learned in the next level I.E. Corrin changing to Paladin at level 5 will learn level 5 Paladin+level 1/10 Cavalier skill in the next few levels.

-Some characters are better in other classes. Azama has absurd physical stats, so it's recommended to Heart Seal him into Apothecary or Dread Fighter ASAP. Hinoka is another popular pick because she has much better defensive stats as a Spear Fighter than as a Sky Knight.

-Many characters have classes that are route specific I.E. Selena as a Sky Knight, Laslow as a Ninja, etc.

-Jakob/Felicia can class change into tier 2 classes with a Heart Seal, meaning once they learn Tomebreaker at 15, they can switch to the Cavalier/Mercenary skills easily.