are dlcs necessary?

[Algérie]

how many hours can I enjoy if I don't buy the dlcs?
I think dlcs are a little bit expensive.And knowing that the contents of the dlc are short

[VertVentus]

29 (Main) ~ 38 (Sides) ~ 58 hours (100%) depending on how complete you are according to How Long to Beat. The biggest obstacles toward 100% are the achievements for:

1. Buying every unique dine-in food at each food stall. Some unlock at the start of every chapter, while Akasaka has limited availability. Kanagawa Port's general store also has limited availability.
   
2. Completing the Workshop, which is gated by a big material grind and some materials are limited (Izuna, Fox Spirit, Giant Joro Spider) behind NG+.
   
3. Completing the Logbook, which requires seeing all 3 endings via NG+ (keep a save before the Ch. 4 decision and Ch. 5 Musashi duel) and has some tricky timing for some entries.

You only need to NG+ once (new scenes, new exclusive ending, features a great auto-skip read text feature that slows down for any new dialogue), but if you want all Battle Recollections (boss rematches) and to max out Iori's MAT, then you'd need to do 4 playthroughs: 3 playthroughs for one of each ending, then you can access Demonic Pageant at the start of your 4th, a boss fight against all 6 main Servants two at a time.

The DLC isn't necessary, but pretty helpful.

• DLC 1 is like 1 hour x 7 stories. It's accessible as soon as Ch. 2 (Lv. 20ish?) but has a recommended Iori level of 45. However, it's safe to play Berserker's story since she starts at Lv. 51 with 6 affinity gauges regardless of your current progress, so you can farm for infinite healing/affinity items, skill jewels, and Mahitotsu Mallets to upgrade Iori's weapons. Beating the DLC unlocks Workshop Renovations for +20 seconds of substitution duration, when the default is 20 seconds and the base-game upgrade for another +20 seconds is gated until Ch. 5. Ch. 5 also lets you do Caster's story, and Ibuki-Douji is the second best Servant in the game. Final Chapter unlocks Rider & Lancer's stories to unlock Gilgamesh, but he's pretty bad since he lacks a NP.
  
• DLC 2 is like 3 hours, accessible at the start of Ch. 3 (Lv. 37ish?) but has a recommended Iori level of 50. Iori gets a skill tree that improves all his stances (Earth Stance can infinitely parry, Void Stance can heal HP to sustain its full health bonus), Workshop Renovations that makes making optimal weapons easier, and Yagyu Munenori is a pretty strong Servant.
  
• DLC 3 is also like 3 hours, accessible halfway through Ch. 3 (Lv. 42ish?) but has a recommended Iori level of 60 (with playable Archer/Lancer sections that start off at Lv. 70 if you're underleveled). Saber gets a new meh skill tree, Workshop Renovations improves Noble Phantasm damage and gem crafting speed, and Kishimojin is the best Servant in the game. Zhao Yun is also pretty strong.

I agree that it is expensive. When the season pass was -30% off for $28 earlier during the summer, that would've been a decent price to purchase it at even if it's only like ~13 hours total. Each DLC also feature more Battle Recollections (11 + 5 + 5 = 21 total) for a little more content though.
The best base game Servants to substitute as are Rogue Assassin (mash Heavy Attack 1, counter most attacks) and Rogue Saber (mash Heavy Attack 2), but the 4 DLC Servants are all better than them and never temporarily unavailable for story reasons.
At the same time as when DLC 3 unlocks is when Battle Recollections unlock, so while you can grind Reminiscence: Vile Serpent (4515 EXP) until you meet the level recommendation, it's better to wait until Ch. 5 for Ibuki-Douji, Void Stance, and Rogue Servant NPs. Wind and Void Stance are your primary methods to deal with monster/Servant Shell Gauges.

[Algérie]

Thank you for your professional and meticulous advice. I will study carefully and make a choice. After listening to your suggestions, I prefer the deluxe version now. Well, I should start saving up for the next sale

[Algérie]

Thank you very much for your detailed explanation, I have benefited a lot! So nice of you,sir!

[King Of Lolis]

If you a hardcore Fate fan then yeah get them
Its always fun to hang out with servants