If a lot of walking is required, 6 8x10 holders, 10 4x5 holders (if shooting only 4x5). If it's roadside, then both 4x5 and 8x10. All holders...15, 8x10. 20, 4x5. I'll usually have HP5, FP4, Shanghai, Adox 100, Efke 25, (as well as Rollei IR, Efke in summer months). I don't use them all...but you never know.