You can just spread the formula over multiple cells. Instead of

  A3: IF(<boolean>, <result if true>, <result if false>)

where each of the three parameters are complex formulae, you can do:

  A3: IF(B3, C3, D3)
  B3: <boolean>
  C3: <X>
  D3: <Y>

Not only is the formula now broken down into simpler chunks, you also get to inspect the component results (like watches in a breakpoint! sorta...). Then you can just hide the relevant columns if you like (B,C,D in this case). You can even use a separate sheet and hide the whole sheet if you wish.