General guidelines advise that those at average risk start regular colonoscopy screening at age 50 until at least 75. The frequency varies between every 10 years or more often depending on screening history and what is found. Earlier or more frequent surveillance is warranted if you have a family history of colorectal issues or relevant symptoms.

In any age group, a colonoscopy is strongly recommended if worrying digestive red flags arise. These include rectal bleeding, iron deficiency anaemia, persistent diarrhoea or constipation, abdominal pain, unexplained weight loss or positive faecal blood. Do not hesitate to consult your GP regarding a colonoscopy if you experience these. Acting quickly maximises the chances of early treatment if any abnormalities exist.

Finally, your doctor may suggest repeat short interval colonoscopies if precancerous polyps were found, or previous colon or rectal cancer exists. This tighter surveillance enables optimal monitoring and prevention.

In summary, from your 50s onwards or if concerning digestive symptoms appear, a timely colonoscopy is critical for ruling out problems and maintaining bowel health. Discussing risk factors with your doctor ensures appropriate screening recommendations.