I am trying to construct a boolean for the following question:

For a given `group` did `cond` change values more than X times? Here is some sample data:

```r
df <- rbind(
  data.frame(
    cond = c("cond1", "cond2", "cond1", "cond2", "cond3"),
    day = 1:5,
    group = "group1"
  ),
  data.frame(
    cond = c("cond1", "cond1", "cond1", "cond1", "cond2"),
    day = 1:5,
    group = "group2"
  )
)

df
#>     cond day  group
#> 1  cond1   1 group1
#> 2  cond2   2 group1
#> 3  cond1   3 group1
#> 4  cond2   4 group1
#> 5  cond3   5 group1
#> 6  cond1   1 group2
#> 7  cond1   2 group2
#> 8  cond1   3 group2
#> 9  cond1   4 group2
#> 10 cond2   5 group2

```

The ordering is relevant here hence the `day` variable. But I am just trying to figure out how to detect when `cond` changes alot and then return those rows. Ideally will be fitting this into a `group_by` then `filter` idiom but really I'm not sure how to construct the boolean.