How do pre-existing conditions affect my health coverage now?

For major medical coverage, they don't — under current ACA rules, insurers can't deny you or charge more because of a pre-existing condition, and they can't exclude treatment for it. That protection applies to employer plans and ACA marketplace plans, so a diabetes or cancer history won't raise your premium or block coverage. The picture is very different for individually underwritten products. Disability insurance, long-term care insurance, and life insurance still use full medical underwriting, meaning a pre-existing condition can raise your premium, trigger an exclusion rider, or get you declined outright. That's exactly why timing matters: lock in disability, LTC, and life coverage while you're healthy, because once a condition appears, those products become expensive or unavailable. So for health insurance, shop freely on price and network; for the underwritten policies, buy early. Don't confuse the two regimes.