Budgeting for Alteration & Prep: What specific line items are often missed?

Hey everyone, I’m wrapping up the location scouting for a period piece drama and now I’m diving deep into budgeting. A seasoned Location Manager mentor always harps on the common mistake of underestimating alteration and prep time, basically the 'hidden labor' that isn’t just straight build-time. I’ve done my best to factor in basic set-dressing and minor structural changes to the locations we’ve secured, but I'm worried I'm missing something crucial in how I'm breaking it down in the budget. What specific line items or categories should a Production Designer (or even us LMs) be pushing for to accurately account for this kind of work in a budget? I want to make sure I’m not setting anyone up for failure later on.