Back Up and Organise Years of Photos Before You Lose Them All

I've got years' worth of photos on my phone (and maybe other devices too) and they're a total mess. I need help getting them sorted before something goes wrong and I lose them. Here are my details:

What devices I have photos on: [e.g. my iPhone, an old Android phone in a drawer, an iPad, a laptop, a digital camera I haven't touched in years]

Roughly how many photos we're talking about: [e.g. a few thousand, honestly probably 10,000+, no idea but my storage is full]

Whether I currently back anything up: [e.g. I think iCloud does something but I'm not sure, I don't back up anything, I've got some on Google Photos, I used to put them on a USB stick but stopped years ago]

What's bothering me most about it: [e.g. I'm terrified my phone will break and I'll lose everything, I can never find a specific photo when I want one, my phone keeps saying storage is full, I've got duplicates everywhere, there are photos of my kids from when they were babies mixed in with screenshots and random photos of parking spaces]

How technical I am: [e.g. not at all — I can just about send an email, fairly comfortable with technology, I know the basics but cloud storage confuses me]

What I'd be willing to spend on this: [e.g. nothing if possible, happy to pay for a cloud service if it's not too expensive, I'd buy an external hard drive if someone told me which one]

Please help me by:

1. First, tell me in plain English what's actually at risk right now — how safe (or not) are my photos based on what I've told you? No scare tactics, just an honest assessment so I know how urgent this is.

2. Give me a step-by-step plan to back everything up properly — starting with the quickest way to protect what I've got RIGHT NOW (today, in 15 minutes), and then a longer-term solution. Explain every step like I've never done it before. Tell me which apps or services to use and roughly what they cost in the UK.

3. Once everything's backed up, give me a realistic system for organising the chaos — how to sort photos into albums or folders I'll actually use, how to get rid of the thousands of screenshots and duplicates clogging things up, and how to find the photos that actually matter (the ones of people, holidays, and milestones) without scrolling through rubbish.

4. Tell me how to set things up so this never happens again — an automatic backup that just runs in the background without me having to think about it.

5. If I mentioned old devices, tell me how to get the photos off those too — step by step, even if the device is old and slow.

6. Give me one small thing I can do in the next 10 minutes to start — because I've been putting this off for ages and I just need to begin.

Keep the tone patient, encouraging, and completely jargon-free. Explain things like I'm smart but not technical. Use British English throughout. Don't recommend anything overly complicated — I want the simplest solution that actually works.