Cloud computing is brilliant. I'm not here to argue otherwise. But there's a specific use case where it consistently costs more than it should, and most developers don't question it until the invoice lands: persistent dev and staging environments.
If you've got a CI runner that's churning away 24/7, a staging server that mirrors production, a self-hosted GitLab instance, a Kubernetes playground, or just a box you want to throw Proxmox on and actually learn virtualisation properly — you're likely paying cloud rates for workloads that don't need cloud flexibility.
A one-time hardware purchase can pay for itself surprisingly quickly. And if you're buying refurbished enterprise kit, faster than you'd think.

The Maths Nobody Does

Let's use a fairly modest example. A small DigitalOcean or Hetzner VPS — 8 vCPUs, 32GB RAM, decent SSD storage — is going to run you somewhere in the region of £80–£120/month depending on the provider and region.
That's £960–£1,440 per year.
A refurbished Dell PowerEdge R630 with dual Xeon E5-2680 v4 processors (28 physical cores / 56 threads), 128GB of registered ECC RAM, and a handful of SSDs will cost you a fraction of that as a one-time purchase. The hardware is enterprise-grade, built to run in data centres around the clock, and has years of useful life in it.
The break-even point on that kind of machine versus a mid-tier VPS is well under 12 months. After that, your infrastructure is essentially free.

"But What About Reliability?"
This is the first objection, and it's a fair one. You're not paying for AWS's redundancy, and a hardware failure is your problem to deal with.
A few honest thoughts on this:
The hardware is more reliable than you might expect. Enterprise servers aren't consumer gear. They're built with redundant power supplies, ECC memory, hardware RAID controllers, and out-of-band management (iDRAC on Dell, iLO on HPE) that lets you diagnose and fix issues remotely without needing physical access. This is kit designed to run without interruption for years.
Certified refurbished means tested. If you're buying from a reputable supplier rather than a random auction lot, the hardware has gone through functional testing. It's not a gamble.
For dev and staging, the risk profile is lower anyway. You shouldn't be running production workloads without redundancy regardless of where they live. For the environments most developers are actually considering self-hosting — CI, staging, dev tooling, personal projects — a brief hardware failure is an inconvenience, not a catastrophe.

What I'd Actually Buy
This is the part where things get interesting, because the refurbished server market has a lot of options and not all of them are the right fit for every workload.
For a self-hosted dev environment, here's roughly how I think about it:
For general-purpose virtualisation (Proxmox, ESXi, etc.)
You want high core count over raw clock speed. The Intel Xeon E5 v3/v4 generation (Haswell/Broadwell) and the Xeon Scalable (Skylake/Cascade Lake) family are both solid, well-supported platforms. Proxmox runs beautifully on them. So does ESXi if you're on an older version — check the VMware HCL if you care about that.
The dual-socket configurations are worth considering if you're planning to run multiple VMs. Two relatively modest CPUs often give you more threads than one premium one, which matters for concurrent workloads.
For RAM — go bigger than you think
Memory is cheap on the refurbished market relative to new. If you're running VMs, 128GB is not excessive — it gives you room to grow without being constrained. Registered ECC RAM is standard on server platforms and genuinely does matter for long-running workloads.
Storage
If your workloads are I/O sensitive (databases, build caches, container layers), NVMe makes a noticeable difference. More recent generation refurbished servers often have NVMe options alongside the traditional SAS/SATA bays. Worth thinking about before you buy.
The configurator approach
I've found the most useful starting point is working through a proper server configurator rather than trying to cross-reference compatibility tables manually. You can work through CPU, memory, and storage options in a structured way and see what's actually available — which matters because the refurbished market doesn't have unlimited stock of every configuration.

A Proxmox Setup in Broad Strokes
If you've not used Proxmox before and you're coming from a cloud background, here's the rough shape of what you're setting up:

Install Proxmox VE on your server (it's Debian-based, boots from USB, installs in about 10 minutes)
Set up your storage pools — ZFS if you want the data integrity guarantees, LVM-thin if you want simplicity
Create VM templates for your standard dev environments — Ubuntu 22.04/24.04, Debian, whatever your projects need
Spin up LXC containers for lightweight services (databases, DNS, monitoring) and VMs for anything that needs kernel isolation
Configure networking — Proxmox's Linux bridge setup is straightforward, and you can set up VLANs if you want to get fancy with network isolation between environments

The web UI is genuinely good. If you're used to managing cloud VMs through a console, Proxmox feels immediately familiar.
For remote access, iDRAC (Dell) or iLO (HPE) gives you a browser-based KVM console — you can access the server as if you're sitting in front of it, even to reinstall the OS. That's the feature that makes remote management actually viable.

What This Looks Like in Practice
A reasonable starting setup for a solo developer or small team:

1U or 2U rack server (or tower if you're working from home and noise matters)
Dual-socket, 16–32 cores total
128GB RAM
2× SSD for OS/VM storage, additional drives for bulk storage if needed

Browse the configurable refurbished servers at Compuwyze if you want to see what that actually costs right now — UK stock, UK warranties, and you can spec to your requirements rather than just taking whatever's listed.
The upfront cost will look significant compared to a monthly VPS bill. Run the 12-month maths and it usually looks very different.

The Honest Downsides
This wouldn't be a useful post if I didn't mention the trade-offs:
Physical space and noise — a 2U rack server is not quiet. If you're in a flat or a shared space, a tower form factor is worth considering, or you'll need a proper comms cabinet with sound dampening. This is a real consideration, not a minor footnote.
Power consumption — enterprise servers draw more power than a NUC or a mini-PC. Factor in electricity costs when you're doing the maths, especially if you're in the UK right now. That said, modern server platforms have improved significantly on power efficiency, and you can tune power profiles in the BIOS.
It's on you — no support ticket to raise if something breaks. You're the sysadmin. For a lot of developers, this is actually the point — you learn things running your own hardware that you won't learn on managed infrastructure. But if you genuinely don't want that responsibility, cloud makes sense.

Worth It?
For developers who want to run persistent environments without ongoing cloud spend, self-hosting on refurbished enterprise hardware is one of the more underrated options. The hardware is capable, the ecosystem (Proxmox, TrueNAS, etc.) is mature, and the economics are genuinely compelling once you stop thinking in monthly costs and start thinking in total cost over two or three years.
It's not for everyone. But if you've been meaning to dig into infrastructure properly, or you're watching your cloud bill creep up month on month, it's worth doing the maths.

Drop any questions in the comments — happy to go deeper on any part of the setup.