Rather than a shredding frenzy, why not just "weed" the older stuff instead. You're fine to shred the small and irrelevant stuff, but you may well benefit from keeping the big/important stuff.
Regardless of number of years, I always keep things like major repairs/renovations/purchase re my house - I have a file going back over 20 years with tradesmen's invoices, appliance bills, receipts for the TV, suites, beds, etc. It's no more than a couple of inches thick so takes up no space. I do the same with my car - always keep everything for each car I've had and then shred a few years after I sell it.
As to bank and c/c statements, I look to see if there's anything interesting on them. If it's just food and fuel, then it gets shredded after the requisite number of years. If there's anything else on there, such as major purchases, holidays, etc., I'll keep it "just in case" - again I've a file no more than an inch or two think of old statements.
Likewise anything to do with tax. I'll shred old payslips after a few years, but I've a file of P60s, P45s, job acceptance letters, contracts of employment, letters from HMRC etc. going right back to my first job over 30 years ago.
You just never know when something will come in handy if you have to prove something. I've certainly made a few claims and got a few refunds for the likes faulty goods years many after purchase, due to inherent design flaws etc which have only been successful because I'd kept the original proof of date of purchase and some documentation showing promises made by the supplier/retailer. With clients, I've also seen where a govt dept has insisted that, say, no NIC was paid 10/20/30 years ago, and it's only been from producing P60 or payslip evidence that we've been able to prove their records are wrong and secured higher benefits for our clients.
The "keep everything for 7 years and then shred" advice is really poor - it should be keep everything at first and then start to weed it out, just keeping stuff that really matters effectively forever.