How to count appearences along a timeline with criteria - excel

Question

I have a table with 3 columns: expense, client_id, date.
The date has record of clients expense for half a year for each day.
Some clients spend many each day, but some not.
The expendure ranging from zero to few hundreds.
I want to group/count active client, which spend over 50 dollars each day, and calculate how much clients was active between 0-30 days, 30-60 days, 60-90 days, 90-120 days, 120-150 days, 150+.
I mean if client spend at least 50 dollars each day along 40 days, i add him to 30-60 days column.
client id appears only once each day.
expense
client_id
date
20
1
01/01/2000
60
2
01/01/2020
70
3
01/02/2020
the result should be like that
0-30 days
30-60 days
60-90 days
90-120 days
9
3
12
20
the values are count of active clients
Thank you a lot

Answer 1

There might be better solutions with less helper columns, but this is what I can offer at the moment.
Preparation
I generated some random data in columns A to C for 10 clients, one month and an expense limit of 100. You will have to adjust the expense threshold and the day ranges to your needs.
Helper columns and formulas
criteria_met checks whether the expense is higher or equal the given threshold (here 10). Formula in D2 is =IF(A2>=10,TRUE,FALSE).
is_consecutive checks whether the client had an entry on the previous day. Formula in E2 is =IF(COUNTIFS(B$1:B1,B2,C$1:C1,C2-1)>0,TRUE,FALSE).
consecutive_group assigns a number for each group of consecutive days, on which the client had an expenditure above or equal the threshold. Formula in F2 is =IF(AND(D2=TRUE,E2=TRUE),MAXIFS(F$1:F1,B$1:B1,B2),MAXIFS(F$1:F1,B$1:B1,B2)+1). Whenever the combination of criteria_met and is_consecutive is FALSE, the group number is increased by one.
days_per_group counts the number of days per client_id and consecutive_group. Formula in G2 is =COUNTIFS(B$1:B2,B2,F$1:F2,F2).
max_per_group makes sure that only the max number of consecutive days is considered per consecutive group. Formula in H2 is =IF(G2=MAXIFS(G:G,B:B,B2,F:F,F2),G2,0).
Result table
labels creates the headline. Formula in J3 is =J2&"-"&K2-1&" days"
values counts how often a number between the given thresholds occured. Formula in J4 is =COUNTIFS($H:$H,">="&I$2,$H:$H,"<"&J$2).
Requirements
Each client can only have one entry per day
The source list (A:C) has to be sorted by date
Please let me know, if you need more information.

Answer 2

how to count values in K4 ?
=COUNTIFS($H:$H,">="&J$2,$H:$H,"<"&K$2)