We’ve probably all sat through sessions, as DM or player, where literally the whole 4-5 hours session passes with shopping, interacting with (in the big picture) inconsequential NPC’s, the like. Now, for some people, this is a great session. And that’s completely fine! That’s the good thing about Dungeons & Dragons, you can play however you want! However, if you’re like me, you’re just sitting there, silently begging for the session to move on with some actually meaningful interactions.
Now, just to clarify, I’m not talking about role playing conversations with NPC’s which might have clues to the overarching plot, or have their own subplots. I’m primarily talking about sessions where the characters are stocking up on rations, buying torches for the poor non-Darkvision, PC’s, etc. Or travel sessions, where nothing much happens. Coincidentally, those are the two areas that I will primarily be discussing.

Shopping
As mentioned, some players might like the shopping “episodes”, where the players go around to various Alchemy Stores, General Goods, Blacksmiths, so on, so forth. However, some may also find that tedious. And to that I simply say – That’s fine. Skip it. Imagine this conversation.
PC1: “Hey guys, can we get some torches? I don’t have Darkvision.”
PC2: “Of course, we have some downtime. Hey DM, is there like a General Store in this town?”

From there, the conversation can go two ways. Either the DM can tell the players whether or not there is a General Store in the vicinity, and the players can head there, interact with the shopkeeper, negotiate a price, so on, so forth. Maybe there’s a minor adventure hook, but more likely, it will literally just be a simple transaction. Alternatively, it is completely ok to, as DM, simply go:
DM: “Of course, you walked past one earlier. How many Torches would you like?”
PC1: “Umm, like 10 for now?”
DM: “Sure thing, that’s just 1 silver, feel free to update your inventory. Anyone else have any shopping they wish to do?”
And that’s the shopping interaction. No roleplay that takes an hour, just a simple transaction.
Now, that being said, if it’s a shop that the players will likely be visiting often, such as a Blacksmith in their hometown, it makes perfect sense to create an NPC to inhabit the store, such as Utab Sorrow Brand, the Orc blacksmith, a refugee from his tribe after his parents, the Chieftains, were slain by Elven assassins. Perhaps the party can establish a friendly rapport with him, and perhaps there will be a small questline pertaining to Utab at some point. But simultaneously, despite this, there doesn’t have to be roleplay EVERY time they visit Utab. There certainly can be, but it’s not necessary.

Travel
Now, this is one that I personally have had a lot of trouble with in the past, in my early days as DM. Recently however, I have come to discover a little secret – You care more about consistency than your players do. Allow me to elaborate.
DM: “Alright, so your journey to Greenest will take around 3 days. Who will take primary watch the first day?”
PC1: “I will, I rolled a 17 in Perception”
DM: “Alright. The day proceeds without worry, and you eventually have to make camp. How do you want to handle this?
PC2: “PC3 and myself will take the first watch, the other two of you can take second watch.”
DM: “Alright. It’s a quiet night, and it passes without issue.”
*repeat for every night*
Now, if nothing happens, this can obviously get very tedious. Now, oftentimes, something may happen. But simultaneously, even though they are an adventuring party, oftentimes travel is just that – travel. Bandit attacks don’t happen every time they step out of city walls, nor do fiendish incursions. If they did, no-one would ever travel anywhere.

Therefore, in my experience, your players genuinely do not care if you handle it differently, such as this.
DM: “Alright, so your journey to Greenest will take around 3 days. Is there anything specific you wish to do during your travels?
PC1: “I want to practice my Elvish with Runael, our guide.”
DM: “Sure thing, you make a little bit of progress towards becoming fluent in Elvish. If there’s no-one else, let us proceed. The first 2 days of your travel, pass without incident. On the third day however, PC3, you notice something on the side of the road…”
*insert encounter*
Or don’t insert an encounter, that’s entirely up to you. My point is, after said encounter, it’s perfectly OK to similarly narrate nothing happening, and the next major event is the party arriving at their destination.

Summary
Not everything has to be narrated. It’s ok to simply say what happens, without having to stick to 100% realism, narrating every small interaction. You (probably) don’t narrate your PC’s going to the bathroom either. In my experience, your players won’t mind, they want stuff to happen too! It is a tabletop role-playing GAME after all. It’s not meant to be a 1-to-1 representation of what life would be like in this fantasy universe.