The evolved form of a Pokemon has better stats than its earlier forms. The majority of Pokemon which evolve using a stone won't learn any moves when evolved, so you don't want to evolve those Pokemon until they've learned all their possible moves. Evolving them earlier will really, really limit their usefulness..
Accordingly, what happens if I stop my Pokemon from evolving?
If you cancel an evolution for a pokemon that evolves when it levels up (I don't know if you can do it otherwise) then if it gains another level it will try to evolve again, so you don't need to capture another one just to get the evolved form.
Similarly, will a Pokemon evolve if you stop the? Can I evolve a Pokémon after stopping the evolution once? Yes, even if you decide to stop an evolution you can change your mind and have that Pokémon evolve later on. That's because the Pokémon will try to evolve again the next time it levels up. And the next time.
Also asked, does evolving Pokemon make them stronger?
Evolving Pokémon gives you a big boost in experience points, so it's one of the main ways by which you'll increase your trainer level. A higher trainer level means stronger Pokémon, plus big rewards each time you earn a new one, so you want to constantly be climbing higher and higher.
Is there a downside to not evolving Pokemon?
There are two disadvantages to evolving a Pokemon though. The first one is pretty minor, and is that a Pokemon takes longer to learn moves in an evolved form (as you noted in your question). The other disadvantage is fairly significant though, and only applies to Pokemon which evolve with an evolution stone.
Related Question Answers
Why shouldn't you evolve your Pokemon?
The only reason to prevent a Pokémon from evolving was if they would miss out on learning a specific move when they leveled up. This was the only reason why you wouldn't evolve a Pokémon at the first opportunity, as the stat boost provided was always worth it.Does not evolving a Pokemon make it weaker?
A Pokemon that isnt evolved is always weaker then a Pokemon that is. Stats are much lower meaning that an evolved Pokemon is always more powerful.Can you evolve a level 100 magikarp?
A level 100 Magikarp will be unable to evolve in the first place, due to it evolving by level.How many times can you stop a Pokemon from evolving?
2 Answers. If you cancel an evolution for a pokemon that evolves when it levels up (I don't know if you can do it otherwise) then if it gains another level it will try to evolve again, so you don't need to capture another one just to get the evolved form.How do I get Sylveon?
Once your Eevee has at least two Affection hearts and knows a Fairy-type move, level it up. You can do this through random battles, fights with other trainers, and so on. Once your Eevee levels up, assuming the conditions above have been met, it should immediately evolve into Sylveon.Why did my Squirtle stop evolving?
If you cancel an evolution for a pokemon that evolves when it levels up (I don't know if you can do it otherwise) then if it gains another level it will try to evolve again, so you don't need to capture another one just to get the evolved form.Can you evolve level 100 Pokemon?
While Pokemon still won't be able to level at the cap, which is level 100, there's a way to fake a level which will now trigger an opportunity to evolve. To do this, players just need to feed their Pokemon a Rare Candy.Should I max CP before evolving?
You should never max out the base pokemon's CP. It could evolve and get bad moves and then you've wasted all the candies maxing it's CP and all the candies on the evolve. The creature's max CP potential remains the same and is solely dependent on the pokemon breed and your personal trainer level.Should I power up Pokemon before evolving?
Because evolving a pokemon only changes the base stats not the level or ivs, it doesn't matter if you power up a pokemon before evolving or after the cp it gets to won't change. But if you care about PVP power up after so you don't go over the cp for what league you what to get it to.Should I power up magikarp before evolving?
There is zero benefit to powering up a Pokemon before the evolution, as their CP is simply taken off their BASE stats. Thus, the best option is to just collect Magikarp until you have 400 candy and select the best option at that time.How do I evolve a null type?
Type: Null will evolve into Silvally when leveled up with high friendship/happiness. You can increase friendship in the following ways: Give Type: Null a Soothe Bell to hold.Should I evolve a lucky Pokemon?
Yes. Evolving a Lucking pokemon will give you an evolved Lucky Pokemon. You won't lose the *Lucky* quality. Here are a few pokemons that I have received them as lucky and evolved them to their highest evolution.Do rare candies make your Pokemon weaker?
Pokémon who evolve at a certain Level will do so normally if a Rare Candy was used to reach that Level. Rare Candies provide no Stat Exp; Pokémon who are raised using this item will therefore tend to be weaker than those who are trained in battle. If you've used Rare Candies on some of your Pokémon, don't worry.What is a lucky Pokemon?
Lucky Pokémon is a special status, separate to Forms or Shinies, that Pokémon can have attached to them. If a Pokémon is Lucky, then the Stardust required to power it up is reduced by 50%.Is leveling up with rare candies bad?
Rare Candies aren't bad at all. They allow you to level up a Pokemon without messing up its EVs, which is really helpful now that the EV reducing berries are harder to obtain, and you need more to completely reduce a stat than you did last gen.Is it worth keeping low CP Pokemon?
While high CP Pokemon don't need to be levelled up as much (they are closer to their maximum level) they can still be weak. Conversely, a Pokemon with a low CP can have perfect IV values.Should I stop Charmander from evolving?
Charmander goes from level 39 to 40 just as fast as Charizard does. But if your Charmander is strong enough to beat up whatever you're fighting, and you'd still like to pick up Flamethrower early, there is no reason to evolve.Can you stop Pokemon from evolve sword and shield?
Sometimes, you just don't want Pokémon to evolve in Sword and Shield. You can attach an Everstone item to your Pokémon, which will stop it from evolving as long as it's equipped. The other method involves spamming the B button every time your Pokémon goes to evolve and the cutscene begins to play.Can you cancel evolution in sword and shield?
There are two main ways you can prevent a Pokémon from evolving in Pokémon Sword and Shield. The first is to press B as the Pokémon is evolving. This will cancel the evolution completely, until the next time the Pokémon levels up. At this point you can either press B again or allow the Pokémon to evolve. 
