It is a very common mix-up but they are definitely different things. Think of it this way: requirements are the rules you follow, while conditions are the actual day-to-day costs of keeping the site running. I found a really helpful article about general conditions in construction that explains the split between site supervision and project admin. In my last project, I almost forgot to budget for the specific permits and the temporary fencing. Now I always make a detailed checklist for things like PPE, site signage, and even the portable toilets. It is way better to be detailed now than to have a budget crisis three months into the job when things get busy. Just take it slow and build your estimate properly every single time to avoid losses.