Is having your OWN support servant necessary?

Having a support is not mandatory, but I would admit without having Waver/Merlin, it is really hard to get through some challenge quests, but it is still doable if you have the right strategy. In Lostbelt, even though they restrict you to only using NPCs, they are actually pretty strong at NP5 with 10/10/10 skills, so as long as you got your team comp right, it should be fine. Even events like the Prison Tower can actually be completed provided that you have good DPS servants

Imo doubling on Waver/Merlin is overkill for most content. I'm not familiar enough with the JP content to say anything about that, but I have to imagine that its possible to complete future challenging content without them (though admittedly having one or both servants would make said content significantly easier.)

What having one or both of them does do is allow you to complete such battles quicker than normal and without convoluted planning, which is an amazing boon when farming since you can accomplish that farming much more quickly and avoid burnout due to sitting for hours on end eating apples and staring at the same battle.

Like you mentioned having more servants gives additional options. It might allow you to fill a hole that prevented you from using some servants.

For me that example would be Vlad that I got from a GSSR. I didn't like him and he felt slower and fragile compared to other berserkers. Since I had neither Waver or Tamamo I felt he couldn't survive long enough to be useful. Heh, I guess the summer event scared me.
At the Halloween rerun I finally drew a Tamamo and therefore eventually started using him in Babylonia for those mixed nodes. I was pleasantly surprised by his damage and how durable he felt.
With proper planning I even used NP's back to back.

I felt restricted during Rashomon as well, I got spooked by Orion but I lacked proper support so I couldn't finish the battle using them.
In the end it came down to Cu squad and sacrifices for Ibaraki's NP. Haha, those battles were far to long to be described as effective.

Until I got Merlin, I was in the camp of only having 3* or less supports, like Hans. And actually, that worked really well for me. He carried through almost all content through Babylon, and rarely died. Using a friend support means using your own servants for DPS, and I don't have anyone amazing at that or have all the bases covered (ST vs AoE with class advantage, or any Rulers or Avengers), so IMHO, it was a lot better to use friend support for DPS, and rely on Hans (don't sell him short--he's great, especially with a Volumen Hyrdagyrum (3T invincibility)). I also used Georgios in the backline (also with a Volumen) to tank in final rounds when necessary.

Personally yes i think you should. I don't really like abusing friend servants it defeats the purpose of raising your own. Then again its entirely up to the person as i have a friend irl that just spams (a borrowed) Cu Alter through everything (all the way to Solomon).

You sure your question shouldn't be 'is having my own Waiver/Merlin necessary?' cause when you say support you seem to only point at them. You dont need either, but there's no denying that it'll make the fight easier for you, more so if you have 2.

No servant is required to have in this game. Keep that in mind.

Having more servants gives you more options. Gives you more wiggle room for CE equipping, for event bonuses adjustment, for teamcomp lenience. Are you going to ask someone on your FL every single time what CE their servant should be wearing?

It's all for convenience. For a better, more optimal farming experience.

Having a Waver (from pretty much the start), I have to say that having your own support is one of the best feelings to breeze through content, because it allows me to use effective strategy while only fielding one trump servant (class counter/berserker/JAlter), then being able to field a *second* trump servant from a friend, allowing me to effectively buff both.

Having said that, logging in I notice that most often "Caster" is my most used servant, and from the servants/teams I see on my friend list, they aren't suffering for being forced to use my Waver for content and seem to be doing quite well with stuff (and now that notes are in the game, we can even say as much - and I have thanked a few for saving my butt with their Servants).

So really... Does having your own Support help? Yes, Immensely, it makes the game smoother, less focus on the strategy aspect and more focus on enjoying the story and gambling aspect of being denied Merlin after spending way more than you should have ;>.< .... But not having one isn't going to destroy your entire experience with the game. In fact, it may even enhance it since you can work more with your own servants and just plug a Friend Waver into place (which allows for more bond diversity - My Waver has literally been in every single fight I've done in this game from the moment I started, which takes up a 16pt slot).

So yeah... No Waver/Merlin = Bond more with your other Servants. Waver/Merlin = Dude is gonna trivialize content for you while you steam roll everything with a perfectly catered team all the time.

Almost nothing is necessary in this game, but having good supports of your own offers a lot of advantages. For one thing, there's all the fp you can get for free from others using your servant. For another, it gives you much greater leeway to choose your own friend supports instead of constantly bringing Wavers and Merlins for farming and hard content.

Gonna give my 2 cents. I have been playing since Rashomon and until just a month ago I had no support servants of my own. I cleared all of Camelot without any support servants and completed all events without one either. I can't speak for future content because I only play NA, but so far I havent had the need for any support servant of my own.

A support like Merlin/Waver/Tamamo definitely makes the game easier and quicker, however it is not required. I completed all singularities and events starting from Rashomon without the use of a support servants of my own. I simply used my friends lol.

TLDR: Not needed, but it makes the game quicker/easier if you have any 1 of Merlin/Tamamo/Waver.