Critical illness cover is a long-term insurance policy that provides a tax-free lump sum upon diagnosis of specific serious conditions, including strokes and cancers, and is intended to ease financial pressures. While these policies can offer significant protection, they vary widely in terms of conditions covered and details like payout structure, and obtaining professional advice is strongly recommended before making changes to existing policies. It's important to consider that not all conditions are covered, and particular age-related exclusions may apply, highlighting the need for careful review and understanding of individual circumstances.