SmileyMiffy

I will soon be starting reno on my new flat. I was just wondering, how do home owners know if the carpentry work done by their ID actually has good workmanship? Are there any ways u can check or spot flaws? Btw my shortlisted ID is from Space Define(a subsidiary of R&R). If anyone has used a designer from that company, please let me know your opinion of that company/designer. Thanks!