Thanks , I ' ll try <| sep |> You are right it ' s more like 45 no idea why I wrote 90 . <| sep |> Competitive lists are presumably built using optimal lands ensuring that all colors are available , spells the lowest cost for a given desired effect , and plenty of card draw and selection draw effects , tutors , looters , etc and as a result tend to be expensive currencywise but can run a higher gastolands ratio than a budget build . Not all lists are built to competitive specs , and may need additional lands in order to hit all their colors or cast the more manaintensive versions of the spells they may be packing , in order to hit the budget available to the player who ' s building the deck . For a beginner , It ' s probably wise to start at 38 , and start working back if you notice a strong tendency to flood , or adding more ramp spells if you find yourself holding things you want to cast but can ' t afford the mana for .