What wrong with my syntax'
sh.Range("F" & lr + 1).Value = Application.WorksheetFunction.Sum(Me.txt_Estimated_Life.Value - Int((Now() - Me.txt_Aquisistion_Date.Value) / 365))
What wrong with my syntax'
sh.Range("F" & lr + 1).Value = Application.WorksheetFunction.Sum(Me.txt_Estimated_Life.Value - Int((Now() - Me.txt_Aquisistion_Date.Value) / 365))
R
It's hard to say what's wrong since you haven't told us what your Userform contains.
Firstly you shouldn't need to use the Sum function (since VBA adds up natively) and secondly if Me.txt_Aquisistion_Date.Value is something like 01/04/2022 then you are trying to subtract (/divide) a text string.
If you type a number like 42 in the UserForm field txt_Estimated_Life and a date like "01/04/2004" in txt_Aquisistion_Date then you probably need to convert the latter to a date using VBA's DateValue function and subtract if from Date (which returns today's date) but round it to 0 decimal places using a worksheet function as follows:
sh.Range("F" & lr + 1).Value = Me.txt_Estimated_Life.Value - Application.WorksheetFunction.RoundDown((Date - DateValue(Me.txt_Aquisistion_Date.Value)) / 365, 0)
Hope this helps.