When using IV TNF inhibitors, do you follow levels to determine if the current dose is adequately treating the patient?

I tend not to get levels, but rather I rely on clinical response; if partial response, often increasing dose (or shorten intervals) can provide dramatic benefit. If the prior response is lost, then consider getting levels and checking for HACAs. I often use TNFi with csDMARDs (e.g., weekly SC methotrexate) to help prevent that and for synergistic benefit.