After taking a look at few new functionalities in the SAP HCM PA landscape under the customer connection program, it's now turn to check out this new option that work in a similar way as validity period for personal area/subareas and employee group/subgroups (1883014 - Validity period of HR objects) and well detailed in Sven Ringling's blog Validity Period for SAP HR Enterprise and Employee Structure while applying to action and reasons for actions.
HR objects validity periods has been out to adapt SAP system with the changing nature of every-businesses... Until then it was not possible to limit in time the existence of a business branch or sub-branch that had been closed down or sold aswell as an employee grouping value that had gone unused that could potentially lead to an incorrect selection. Well overtime a reason for action might for the same motto become obsolete in the system; and while in the past you would have developed a customer check to prevent your end-user to potentially select a erroneous value nowadays you can use a standard solution classified with "Idea D6809".
A new table T530_DELIMIT will let you customize time-validity for your corresponding reason for actions entries in T530; activating a switch in T77S0 will route ABAP routine to an evaluation check to prevent an potential inconsistencies to being recorded.
SAP under notes 2162738 - Selection restriction for action types; validity period for action reasons& 2162746 - Interface note: Selection restriction for action types; validity period for action reasons both published late April this year and parts of SP93 for EHP4 & SP21 for EHP8 as enabled this option; however it only applies to PA40 (personal actions) leaving editing in PA30 possible.There is also a part dedicated for HR-Renewal (EA-HRGXX) SP level 44 for EHP7 and 21 for EHP8 to adapt your roadmaps.
If you don't want to wait for the respective SP, you can SNOTE 2162746 in your system (there might be a bit of manual activities on-hand)... anyhow the following object would becomes available in your system:
| Program ID | Object Type | Object Name |
| LIMU | CINC | CL_HRPAD_SWITCH_ADMIN_DELIA===CCDEF |
| LIMU | CINC | CL_HRPAD_SWITCH_ADMIN_DELIA===CCIMP |
| LIMU | CINC | CL_HRPAD_SWITCH_ADMIN_DELIA===CCMAC |
| LIMU | CLSD | CL_HRPAD_SWITCH_ADMIN_DELIA |
| LIMU | CPUB | CL_HRPAD_SWITCH_ADMIN_DELIA |
| LIMU | FUNC | HRPAD_COLLECTIVE_MASSG_F4EXIT |
| LIMU | FUNC | HRPAD_COLLECTIVE_MASSN_F4EXIT |
| LIMU | FUNC | HRPAD_FILL_MASSN_LISTBOX_UGR |
| LIMU | FUNC | HRPAD_MASSG_F4_EXIT |
| LIMU | FUNC | HRPAD_MASSN_F4_EXIT |
| LIMU | METH | CL_HRPAD_SWITCH_ADMIN_DELIA CLASS_CONSTRUCTOR |
| LIMU | METH | CL_HRPAD_SWITCH_ADMIN_DELIA IS_ACTIVE |
| LIMU | REPS | LHRPAD_DELIMIT_ACTIONSF01 |
| LIMU | REPS | LHRPAD_DELIMIT_ACTIONSTOP |
| LIMU | REPS | SAPLHRPAD_DELIMIT_ACTIONS |
And if you have HR-Renewal feature switched-on:
| Program ID | Object Type | Object Name |
| LIMU | METH | CL_HRASR00_DT_FST_PA_ACTN_INFOPROCESS_VALUE_HELP |
| LIMU | METH | CL_HRASR00_START_SEGMENT IF_FPM_GUIBB_FORM~GET_DEFINITION |
SAP note 2162746 - Interface note: Selection restriction for action types; validity period for action reasons only consist of manual activities to activates the functionality and customize your entries.
(1) set a flag in T77S0 table under switch ADMIN and semantic abbreviation DELIA (Activate Limited Validity of Action Types/Reasons)
no need to worry about the warning message 
(2) further editing customizing entries in V_T530_DELIMI to limit any of your reason for actions.
New messages #1: MASSG is not valid any more at begin date of the IT record or #2: MASSG is not yet valid at begin date of the IT record will be generated whenever conditions are met.