Well, it's quite true and just like i said there's isn't anything actually wrong in buying monthly so far the input is consistent just that I also prefer the weekly compared to the monthly besides I'm also in my accumulation stage and the weekly buying method could improve the efficiency of price entry (though not always but most times it proves it worth) and about the fee I think that could also be put into consideration but taking 4 inputs/per month shouldn't be to much to pull when the need for consolidation arises... though if compared to single input/address its quite preferrable over 4inputs/month but still there will still be a need to consolidate so I think the fee difference shouldn't be too much so far the inputs isn't much.
I was also thinking that when you have many small UTXO that consolidation is good when TX fees get low, but I have come to realize that consolidation of transaction will only be helpful to those investors who are being paid in bitcoin direct to their private wallet.
A new investor who is using DCA to purchase small unit of bitcoin weekly will not be able to consolidate his UTXO because if he is buying fro an exchange which will be very discouraging for him to send immediately after buying when TX fees are high and that is why whoever is buying weekly from an exchange just need to relax for a while but keep on buying regularly and keeping it in an exchange till transaction fees are low again before he can send it to his private wallet.