Relationships have no expiration date. After any gap, assume they'll be happy to hear from you, and reach out with no agenda.
The idea
"It's been so long, they're going to wonder why I'm reaching out." I hear it constantly. It's a myth. Relationships aren't perishable goods. The other person isn't sitting at their kitchen table stewing about why you haven't written; if anything, they feel guilty they haven't written you. And the fear of looking like you have an agenda has a simple antidote: don't have one. Meanwhile, those old relationships already have trust banked. You did the hard part years ago.
How to do it
Sort your CRM or your texts by least recently contacted.
Find the name that makes you wince a little and that you genuinely want back.
Send a short, sincere message. No long explanation, no apology for the silence.
Leave the ball in their court.
Example
I honestly can't think of a single time a "long time no talk" message was met with rejection. At worst, silence, which was there before. Somewhere in your phone is a person who'd take your call today, vouch for you tomorrow and celebrate your next win, and you haven't talked to them in eighteen months. Meanwhile you're on a Zoom with a stranger. Research on dormant ties backs the instinct: reconnecting often yields more than a brand new contact, because trust plus fresh perspective is a rare combination.
Script
"Hey! Long time no talk. Just thought of you."
Watch out for
"Never too late" assumes you didn't set the bridge on fire. If you did, see The Out-of-the-Blue Apology.
Relatable: Relatable's suggestions flag who you've gone quiet on, which makes a good starting list. Sorting any contact list or your texts by last contact works too. How-to: Know who to reach out to next.
Related frameworks
Reconnecting After a Long Silence: Skip the apology. Send a short note that they came to mind, ideally with one real detail or shared memory, and leave the ball in their court.
The Antilibrary of Relationships: Everyone has far more lapsed relationships than maintained ones. Fading is natural, and any of them can be pulled back off the shelf.
Relationship Debt: Some drift is a fair tradeoff if you take it on knowingly. Pay it back with a short, honest note instead of an elaborate apology.
The Liking Gap: People like us more than we think and enjoy compliments and outreach far more than we predict, so say the kind thing.